Process for the production of phenylalkanes that use a zeolitic catalyst that is based on silica-alumina

ABSTRACT

An alkylating process for the production of at least one of 2-, 3-, 4-, 5-, and 6-phenylalkanes by alkylation of an aromatic compound with a feedstock containing at least one olefin comprising at least 9 carbon atoms per molecule, in the presence of a catalyst comprising at least one substrate based on at least a zeolite and a non-zeolitic silica-alumina matrix with a low content of macropores, whereby said matrix contains an amount of more than 5% by weight and less than or equal to 95% by weight of silica (SiO 2 ), whereby said process is carried out at a temperature of between 30 and 400° C., a pressure of between 0.1 and 10 MPa, an hourly volumetric flow rate of 0.50 to 200 h −1 , and an aromatic compound/olefin molar ratio of between 1:1 and 50:1.

CROSS REFERENCE TO RELATED APPLICATION

Application PCT/FR04/03.270 relates to the substrates and/or catalystsdescribed in this application.

TECHNICAL FIELD

This invention relates to the field of the processes of production ofphenylalkanes by alkylation of aromatic compounds by means of at leastone olefin that comprises at least 9 carbon atoms per molecule. Moreparticularly, for example, a hydrocarbon fraction that comprises atleast one olefin that has 9 to 16 carbon atoms or 10 to 14 carbon atomsper molecule or, for example, a hydrocarbon fraction that comprises atleast one olefin that has 14 to 20 carbon atoms, in the presence of atleast one catalyst that is supported on a substrate that comprises aparticular silica-alumina matrix and at least one zeolite, will be used.

PRIOR ART

The phenylalkanes that are obtained according to the inventionconstitute compounds for the formulation, after sulfonation, ofbiodegradable detergents.

Currently, the bases for biodegradable detergents rely extensively onlinear alkylbenzenes. The production of this type of compound is growingsteadily. One of the primary properties sought for these compounds,after the sulfonation stage, is, in addition to their detergent power,their biodegradability. To ensure maximum biodegradability, the alkylgroup should be linear and long, and the distance between the sulfonategroup and the terminal carbon of the linear chain should be as great aspossible. The most advantageous agents for alkylation of benzene consistof C9-C16 linear olefins, and preferably C10-C14 linear olefins.

The linear alkylbenzenes that are obtained by alkylation of aromaticcompounds, preferably by alkylation of benzene by means of (a) linearolefin(s), are prepared today by two major processes. During the stagefor alkylation of benzene or aromatic compounds, the first process useshydrofluoric acid as an acid catalyst. The second uses aFriedel-Craft-type catalyst, in particular with an AlCl₃ base. These twoprocesses lead to the formation of 2-, 3-, 4-, 5- and 6-phenylalkanes.The primary drawback of these processes is linked to environmentalconstraints. The first process that is based on the use of hydrofluoricacid poses severe safety problems, on the one hand, and waste treatmentproblems, on the other hand. The second process poses the standardproblem of processes that use Friedel-Craft catalysts, in this case theproblem of wastes. Actually, for this type of process, it is necessaryto neutralize the effluents by a basic solution at the outlet of thereactor. Added to these various drawbacks for the two processes are thedifficulties that are linked to the separation of the catalyst from theproducts of the reaction.

These various constraints explain the advantage of developing a processfor alkylation of aromatic compounds by olefins, in particular thelinear olefins, in the presence of a solid catalyst.

The prior art notes the use of various types of catalysts such ascrystallized catalysts that have geometric selectivity properties suchas the zeolites (U.S. Pat. No. 4,301,317), clays, amorphous catalystssuch as the silica-aluminas or the catalysts that are based on supportedheteropolyanions.

U.S. Pat. No. 5,344,997, U.S. Pat. No. 5,245,094 and U.S. Pat. No.5,302,732 describe the use of amorphous silica-aluminas, with or withoutthe presence of fluorine and/or with very low sodium contents withSiO₂—Al₂O₃ compositions in the range of 1:1 to 9:1, and preferably inthe range of 65:35 to 85:15 and in particular 75:25. The solids that aredisclosed are therefore for the most part silicic. The selectivity ofthe products of the reaction is described as increasing with the silicacontent.

OBJECT OF THE INVENTION

We discovered that the use of catalysts that comprise a substrate thatis based on at least one zeolite and that is based on a particularnon-zeolitic silica-alumina matrix, by alkylation of aromatic compoundsby means of olefin(s) as defined above, made it possible to obtainhigher catalytic performance levels than those of the catalysts that aredescribed in the prior art. In particular, these new catalysts are atthe same time very active, very selective and very resistant todeactivation. Hereinafter, any reference to a silica- or silico-aluminais meant to define a non-zeolitic silica- or silico-alumina.

DETAILED DESCRIPTION OF THE INVENTION

The invention relates to a process for the production of at least onecompound that is selected from among the 2-, 3-, 4-, 5-, and6-phenylalkanes by alkylation of an aromatic compound, preferably byalkylation of benzene, by means of at least one olefin that contains atleast 9 carbon atoms per molecule, in the presence of a catalyst thatcomprises at least one substrate that is based on at least one zeoliteand that is based on a particular silica-alumina, whereby saidalkylation reaction is carried out under a pressure of about 0.1 to 10MPa, a temperature of about 30 to 400° C., an hourly volumetric flowrate of about 0.5 to 200 h⁻¹, and a molar ratio of the aromatic compoundto all the olefin(s) contained in the feedstock of about 1:1 to 50:1.The invention relates most particularly to the alkylation of an aromaticcompound by means of a linear olefin for the purpose of producing linearphenylalkanes.

Within the framework of this invention, the hydrocarbon feedstock thatis used to carry out the alkylation of the benzene core can contain, inaddition to at least one olefin as defined above, one or more paraffins,one or more other aromatic compound(s), one or more polyolefiniccompound(s) (for example diolefinic compound(s)), one or more mono-and/or poly-unsaturated non-linear olefin(s) and optionally hydrogen.These fractions can also contain one or more alpha-olefin(s) in a veryvariable amount from the trace state up to very large amounts, and evenin the majority for the most part relative to said feedstock. Theolefins can be linear or branched olefins. The hydrocarbon feedstockpreferably comprises a majority of paraffins.

The process according to this invention makes it possible to produce,preferably simultaneously, at least one compound that is selected fromamong the 2-, 3-, 4-, 5-, and 6-phenylalkanes. In the case where thefeedstock comprises linear olefins, the process according to theinvention makes it possible to produce linear phenylalkanes for the mostpart. In the case where the feedstock comprises branched olefins, theprocess according to the invention makes it possible to produce branchedphenylalkanes for the most part.

The catalyst that is used in this invention comprises at least onesilica-alumina that has particular characteristics.

The catalyst that is used in this invention also comprises at least onezeolite. Thus, the substrate of the catalyst comprises an intimatemixture comprising (A) at least one zeolite and (B) a non-zeoliticsilica-alumina matrix.

The applicant discovered in particular that, preferably and in asurprising way, the interaction between the zeolite and thesilica-alumina creates an effect of synergy with respect to BET surfacethat makes it possible to obtain very good catalytic properties in termsof alkylation of aromatic compounds.

In addition, this catalyst that is shaped in, for example, the form ofballs or extrudates, exhibits good mechanical resistance.

Characterization Techniques

In the following specification of the invention, specific surface areais defined as the B.E.T. specific surface area that is determined bynitrogen adsorption according to the ASTM D 3663-78 standard establishedfrom the BRUNAUER-EMMETT-TELLER method that is described in theperiodical “The Journal of American Society,” 60, 309, (1938).

In the following specification of the invention, “mercury volume” of thesubstrates and catalysts is defined as the volume that is measured bymercury porosimeter intrusion according to the ASTM D4284-83 standard ata maximum pressure of 4000 bar, using a surface tension of 484 dyne/cmand a contact angle for the amorphous silica-alumina substrates of 140°.The mean mercury diameter is defined as being a diameter such that allthe pores of a size smaller than this diameter constitute 50% of thepore volume (V_(Hg)) in an interval encompassed between 36 Å and 1000 Å.One of the reasons for which it is preferable to use the substrate as abase to define the pore distribution resides in the fact that thecontact angle of the mercury varies after impregnation of the metalsbased on the nature and the type of metals. The wetting angle wasassumed to be equal to 140° by following the recommendations of the work“Techniques de l'ingénieur, traité, analyse et caractérisation[Engineering Techniques, Treatise, Analysis, and Characterization],” pp.1050-5, J. Charpin and B. Rasneur.

To obtain better precision, the value of the mercury volume in ml/gprovided in the following text corresponds to the value of the totalmercury volume in ml/g that is measured in the sample less the value ofthe mercury volume in ml/g measured in the same sample for a pressurethat corresponds to 30 psi (about 2 bar). The mean mercury diameter isalso defined as being a diameter such that all the pores of a size lessthan this diameter constitute 50% of the total mercury pore volume.

So as to better characterize the pore distribution, the following poredistribution criteria in terms of mercury are finally defined: volume V1corresponds to the volume that is contained in the pores whose diameteris less than the mean diameter minus 30 Å. Volume V2 corresponds to thevolume that is contained in the pores with a diameter that is greaterthan or equal to the mean diameter minus 30 Å and less than the meandiameter plus 30 Å. Volume V3 corresponds to the volume that iscontained in the pores with a diameter that is greater than or equal tothe mean diameter plus 30 Å. Volume V4 corresponds to the volume that iscontained in the pores whose diameter is less than the mean diameterminus 15 Å. Volume V5 corresponds to the volume that is contained in thepores with a diameter that is greater than or equal to the mean diameterminus 15 Å and less than the mean diameter plus 15 Å. Volume V6corresponds to the volume that is contained in the pores with a diameterthat is greater than or equal to the mean diameter plus 15 Å.

The pore distribution that is measured by nitrogen adsorption wasdetermined by the Barrett-Joyner-Halenda (BJH) model. The nitrogenadsorption-desorption isotherm according to the BJH model is describedin the periodical “The Journal of American Society,” 73,373, (1951)written by E. P. Barrett, L. G. Joyner and P. P. Halenda. In thefollowing specification of the invention, nitrogen adsorption volume isdefined as the volume that is measured for P/P_(O)=0.99, pressure forwhich it is assumed that nitrogen filled all the pores. The meannitrogen desorption diameter is defined as being a diameter such thatall of the pores that are smaller than this diameter constitute 50% ofthe pore volume (V_(P)) measured on the desorption branch of thenitrogen isotherm.

Adsorption surface area is defined as the surface area that is measuredon the branch of the adsorption isotherm. Reference will be made to, forexample, the article by A. Lecloux “Mémoires Société Royale des Sciencesde Liège,” 6^(ème) série [6^(th) Series], Tome I [Volume 1], fasc. 4[Section 4], pp. 169-209 (1971).

The sodium content was measured by atomic absorption spectrometry.

X diffraction is a technique that can be used to characterize thesubstrates and catalysts according to the invention. In the followingspecification, the analysis of x rays is carried out on powder with aPhilips PW 1830 diffractometer that operates in reflection and isequipped with a rear monochromator by using CoKalpha radiation(λK_(α1)=1.7890 Å, λK_(α2)=1.793 Å, intensity ratio K_(α1)/K_(α2)=0.5).For the X diffraction diagram of the gamma-alumina, reference will bemade to the ICDD data base, form 10-0425. In particular, the two mostintense peaks are located at a position that corresponds to one dencompassed between 1.39 and 1.40 Å and one d encompassed between 1.97 Åto 2.00 Å. d is called the inter-reticular distance that is derived fromthe angular position by using Bragg's equation:(2d _((hk1))*sin(θ)=η*λ).

Gamma-alumina is defined in the text below, i.a., as, for example, analumina contained in the group that consists of cubic gamma-aluminas,pseudo-cubic gamma-aluminas, tetragonal gamma-aluminas, poorly orslightly crystallized gamma-aluminas, large-surface gamma-aluminas,small-surface gamma-aluminas, gamma-aluminas that are obtained fromcoarse boehmite, gamma-aluminas that are obtained from crystallizedboehmite, gamma-aluminas that are obtained from boehmite that isslightly or poorly crystallized, gamma-aluminas that are obtained from amixture of crystallized boehmite and an amorphous gel, gamma-aluminasthat are obtained from an amorphous gel, and gamma-aluminas evolvingtoward delta. For the positions of diffraction peaks of eta-, delta- andtheta-aluminas, it is possible to refer to the article by B. C. Lippensand J. J. Steggerda in “Physical and Chemical Aspects of Adsorbents andCatalysts,” E. G. Linsen (Ed.), Academic Press, London. 1970, pp.171-211.

For the substrates and catalysts according to the invention, the Xdiffraction diagram demonstrates a wide peak that is characteristic ofthe presence of amorphous silica. Furthermore, in the entire text thatfollows, the alumina compound can contain an amorphous fraction that isdifficult to detect by the DRX techniques. It will therefore beunderstood below that the alumina compounds that are used or describedin the text can contain an amorphous or poorly crystallized fraction.

A method of characterization of the substrates and catalysts accordingto the invention that can be used is transmission electronic microscopy(TEM). For this purpose, an electronic microscope (such as Jeol 2010 orPhilips Tecnai 20F, optionally with scanning) that is equipped with anenergy dispersion spectrometer (EDS) for x-ray analysis (for example aTracor or an Edax) is used. The EDS detector should make possible thedetection of light elements. The combination of these two tools, TEM andEDS, makes it possible to combine the imagery and the local chemicalanalysis with good spatial resolution.

For this type of analysis, the samples are finely ground in the drystate in a mortar; the powder is then included in the resin to produceultrafine fractions with a thickness of about 70 nm. These fractions arecollected on copper grids that are covered by an amorphous carbon filmwith holes used as a substrate. They are then introduced into themicroscope for observation and analysis under secondary vacuum. Byimagery, the sample zones are then easily distinguished from the resinzones. A certain number of analyses, 10 at a minimum, preferably between15 and 30, are then initiated on different zones of the industrialsample. The size of the electronic beam for the analysis of the zones(approximately determining the size of the analyzed zones) is 50 nm ofdiameter at a maximum, preferably 20 nm, even more preferably 10, 5, 2or 1 nm of diameter. In the scanned mode, the analyzed zone will bebased on the size of the scanned zone and no longer on the size of thebeam, which is generally small.

The zeolites that are used for the preparation of catalysts that can beused in the process according to the invention are characterized byseveral values such as their SiO₂/Al₂O₃ framework molar ratio, theircrystalline parameter, their pore distribution, their specific surfacearea, their sodium ion uptake capacity, or else their water vaporadsorption capacity.

The peak rate and the crystalline fraction are important parameters toconsider. The peak rates and the crystalline fractions are determined byx-ray diffraction relative to a reference zeolite, by using a procedurederived from the ASTM D3906-97 method “Determination of Relative X-RayDiffraction Intensities of Faujasite-Type-Containing Materials.” It willbe possible to refer to this method for the general conditions ofapplication of the procedure, and, in particular, for the preparation ofsamples and references.

A diffractogram consists of the characteristic lines of the crystallizedfraction of the sample and of a background, created essentially by thediffusion of the amorphous or microcrystalline fraction of the sample (aweak diffusion signal is related to the equipment, air, sampling device,etc.). The peak rate of a zeolite is the ratio, in a predefined angularzone (typically 8 to 40° 2θ when copper radiation Kα, 1=0.154 nm, isused), of the area of the lines of the zeolite (peaks) to the overallarea of the diffractogram (peaks+background). Thispeaks/(peaks+background) ratio is proportional to the amount of zeolitethat is crystallized in the material. To estimate the crystallinefraction of a Y zeolite sample, the peak rate of the sample will becompared to that of a reference considered to be 100% crystallized (NaY,for example). The peak rate of a completely crystallized NaY zeolite ison the order of 0.55 to 0.60.

The semi-quantitative treatment of X spectra collected with the aid ofthe EDS spectrometer makes it possible to obtain the relativeconcentration of Al and Si (in % atomic) and the Si/Al ratio for each ofthe analyzed zones. It is then possible to calculate the Si/Al_(m) meanand the standard deviation σ of this set of measurements. In thenon-limiting examples of the following specification of the invention,the 50 nm probe is the probe that is used to characterize the substratesand catalysts according to the invention, unless otherwise indicated.

The packing density (DRT) is measured in the manner that is described inthe work “Applied Heterogeneous Catalysis” by J. F. Le Page, J. Cosyns,P. Courty, E. Freund, J.-P. Franck, Y. Jacquin, B. Juguin, C. Marcilly,G. Martino, J. Miguel, R. Montamal, A. Sugier, H. Van Landeghem,Technip, Paris, 1987. A graduated cylinder with acceptable dimensions isfilled by successive additions, and between each addition, the catalystis packed by shaking the cylinder until a constant volume is achieved.This measurement is generally carried out on 1000 cm³ of catalyst packedinto a cylinder whose height to diameter ratio is close to 5:1. Thismeasurement can preferably be carried out on automated devices such asAutotap® that is marketed by Quantachrome.

The acidity of the matrix is measured by infra-red (IR) spectrometry.The IR spectra are recorded on a Nicolet interferometer such asNexus-670 under a resolution of 4 cm⁻¹ with a Happ-Genzel-typeapodization. The sample (20 mg) is pressed into the form of aself-supported pellet and placed in an in-situ analysis cell (25° C. to550° C., furnace offset from the IR beam, secondary vacuum of 10⁻⁶mbar). The diameter of the pellet is 16 mm.

The sample is pretreated in the following way to eliminate thephysisorbed water and to dehydroxylate partially the surface of thecatalyst in order to have a representative image of the acidity of thecatalyst in use:

-   -   Increase in temperature from 25° C. to 300° C. in 3 hours,    -   Stage of 10 hours at 300° C., and    -   Drop in temperature from 300° C. to 25° C. in 3 hours.

The basic probe (pyridine) is then adsorbed with saturating pressure at25° C. and then thermo-desorbed according to the following stages:

-   -   25° C. for 2 hours under secondary vacuum,    -   100° C. for 1 hour under secondary vacuum,    -   200° C. for 1 hour under secondary vacuum, and    -   300° C. for 1 hour under secondary vacuum.

A spectrum is recorded at 25° C. at the end of the pretreatment and ateach desorption stage in transmission mode with an accumulation time of100 s. The spectra are set to iso-mass (therefore assumed to be atiso-thickness) (20 mg exactly). The number of Lewis sites isproportional to the surface area of the peak whose maximum lies around1450 cm⁻¹, including any shoulder. The number of Bronsted sites isproportional to the surface area of the peak whose maximum is locatedtoward 1545 cm⁻¹. The ratio of the number of Bronsted sites/number ofLewis sites (B/L) is estimated to be equal to the ratio of the surfaceareas of two peaks described above. The surface area of peaks at 25° C.is generally used. This B/L ratio is generally calculated starting fromthe spectrum that is recorded at 25° C. at the end of the pretreatment.

Description of the Process

More specifically, the invention relates to a process for the productionof at least one compound that is selected from among the 2, 3-, 4-, 5-,and 6-phenylalkanes by alkylation of an aromatic compound (preferablybenzene) by means of at least one olefin that comprises at least 9carbon atoms per molecule, in the presence of a catalyst that comprisesat least one substrate that is based on at least one zeolite and that isbased on a silica-alumina matrix, whereby said matrix contains an amountthat is more than 5% by weight and less than or equal to 95% by weightof silica (SiO₂), whereby said catalyst exhibits the followingcharacteristics:

-   -   A mean pore diameter, measured by mercury porosimetry,        encompassed between 20 and 140 Å,    -   A total pore volume, measured by mercury porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g,    -   A total pore volume, measured by nitrogen porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g,    -   A BET specific surface area encompassed between 100 and 850        m²/g,    -   A packing density after calcination of more than 0.65 g/cm³,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.02 ml/g,    -   An X diffraction diagram that contains at least the main lines        that are characteristic of at least one of the transition        aluminas contained in the group that consists of the alpha-,        rho-, chi-, eta-, gamma-, kappa-, theta- and delta-aluminas,    -   Preferably a pore distribution such that the ratio between        volume V2, measured by mercury porosimetry, encompassed between        D_(mean)−30 Å and D_(mean)+30 Å, to the total mercury volume is        more than 0.6, such that volume V3, measured by mercury        porosimetry, encompassed in the pores with diameters of more        than D_(mean)+30 Å, is less than 0.1 ml/g, and such that volume        V6, measured by mercury porosimetry, encompassed in the pores        with diameters of more than D_(mean)+15 Å, is less than 0.2        ml/g,        whereby said process is conducted at a temperature of between 30        and 400° C., a pressure of between 0.1 and 10 MPa, an hourly        volumetric flow rate of 0.05 to 200 h⁻¹, and an aromatic        compound/olefin molar ratio of between 1:1 and 50:1.        Characteristics of the Catalyst

The catalyst that is used in the process according to this inventioncomprises a substrate that is based on at least one zeolite and that isbased on a silica-alumina matrix, and it exhibits the followingcharacteristics:

-   -   A content by mass of silica (SiO₂) that is more than 5% by        weight and less than or equal to 95% by weight, preferably        encompassed between 10 and 80% by weight, more preferably a        silica content of more than 20% by weight and less than 50% by        weight, and even more preferably more than 20% by weight and        less than 40% by weight,    -   A mean pore diameter, measured by mercury porosimetry,        encompassed between 20 and 140 Å, preferably between 40 and 120        Å, and even more preferably between 50 and 100 Å,    -   Preferably a ratio between volume V2, measured by mercury        porosimetry, encompassed between D_(mean)−30 Å and D_(mean)+30        Å, to the total pore volume that is also measured by mercury        porosimetry of more than 0.6, more preferably more than 0.7, and        even more preferably more than 0.8,    -   Preferably a volume V3 that is encompassed in the pores with        diameters of more than D_(mean)+30 Å, measured by mercury        porosimetry, of less than 0.1 ml/g, more preferably less than        0.06 ml/g, and even more preferably less than 0.04 ml/g,    -   Preferably a ratio between volume V5 that is generally        encompassed between D_(mean)−15 Å and D_(mean)+15 Å, measured by        mercury porosimetry, and volume V2 that is encompassed between        D_(mean)−30 Å and D_(mean)+30 Å, measured by mercury        porosimetry, of more than 0.6, more preferably more than 0.7,        and even more preferably more than 0.8,    -   Preferably a volume V6 that is encompassed in the pores with        diameters of more than D_(mean)+15 Å, measured by mercury        porosimetry, of less than 0.2 ml/g, more preferably less than        0.1 ml/g and even more preferably less than 0.05 ml/g,    -   A total pore volume, measured by mercury porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g, preferably between        0.1 and 0.5 ml/g and even more preferably between 0.1 and 0.4        ml/g,    -   A total pore volume, measured by nitrogen porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g, preferably        encompassed between 0.1 and 0.5 ml/g, and even more preferably        between 0.1 and 0.4 ml/g,    -   A BET specific surface area encompassed between 100 and 850        m²/g, preferably encompassed between 150 and 650 m²/g, and more        preferably between 200 and 600 m²/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g and even more preferably        less than 0.03 ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.025 ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.025 ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g, and more preferably less        than 0.02 ml/g,    -   A packing density of more than 0.65 g/cm³, preferably more than        0.80 g/cm³, very preferably more than 0.95 cm³/g, and even more        preferably more than 1.05 g/cm³,    -   An X diffraction diagram, characterized in that it contains at        least the main lines that are characteristic of at least one of        the transition aluminas contained in the group that consists of        the rho-, chi-, kappa-, eta-, gamma-, theta- and delta-aluminas,        and preferably characterized in that it contains at least the        main lines that are characteristic of at least one of the        transition aluminas contained in the group that consists of the        gamma-, eta-, theta- and delta-alumina, and more preferably        characterized in that it contains at least the main lines that        are characteristic of the gamma-alumina and eta-alumina, and        even more preferably characterized in that it contains the peaks        at one d encompassed between 1.39 to 1.40 Å and at one d        encompassed between 1.97 Å to 2.00 Å.    -   The catalyst also contains:    -   Optionally at least one hydro-dehydrogenating element that is        selected from the group that is formed by the noble elements of        group VIII or of group VIB of the periodic table. The catalyst        preferably contains at least one noble element of group VIII        that is selected from the group that is formed by platinum,        palladium and ruthenium. The platinum-palladium combination is        even more preferred. The content by mass of noble metals of        group VIII or metals of group VIB, in metallic form or in oxide        form, is generally encompassed between 0.005 and 5% by weight,        preferably between 0.01 and 3% by weight and even more        preferably between 0.05 and 1% by weight; and    -   Optionally at least one halogenated element, preferably selected        from the group that is formed by chlorine and fluorine. More        preferably, the halogen that is introduced into the catalyst is        fluorine. The contents by mass of halogen are encompassed        between 0.5 and 10%, preferably between 1 and 5%. According to        an embodiment of the invention, the zeolite that is included in        the substrate, used by itself or in a mixture with other        zeolites, is selected from the FAU group, in particular from the        group that is formed by the Y zeolite and the Y zeolites that        have undergone a secondary treatment such as, in particular:        USY, VUSY, SDUSY, HMUSY and DAY.

The Y zeolite that is used in the catalysts according to the inventionis at least in part in hydrogen form or acid form (H⁺) or ammonium form(NH₄ ⁺) or cationic form, whereby said cation is selected from the groupthat is formed by the groups IA, IB, IIA, IIB, IIIA, IIIB (including therare earths), Sn, Pb and Si; it is preferably at least in part in H⁺form or it can also be used at least in part in cationic form (asdefined above).

According to another embodiment of the invention, the zeolite is azeolite that is selected from the group that is formed by the mordenite,beta, NU-87, and EU-1 zeolites, preferably the MOR zeolite, used byitself or in a mixture with other zeolites.

In an embodiment of the invention, the catalyst contains a matrix thatcomprises at least two silico-aluminum zones, whereby said zones haveSi/Al ratios that are less than or greater than the overall Si/Al ratiothat is determined by X fluorescence. Thus, a matrix that has an Si/Alratio that is equal to 0.5 comprises, for example, two silico-aluminumzones; one of the zones has an Si/Al ratio that is determined by TEM tobe less than 0.5, and the other zone has an Si/Al ratio that isdetermined by TEM to be between 0.5 and 2.5.

In another embodiment of the invention, the catalyst contains a matrixthat comprises a single silico-aluminum zone, whereby said zone has anSi/Al ratio that is equal to the overall Si/Al ratio that is determinedby X fluorescence and is less than 2.3.

The catalyst that can be used in the process according to the inventionpreferably exhibits a bed crushing value, determined according to theSHELL method (SMS 1471-74) and characterizing its mechanical resistance,of more than 0.5 MPa.

The acidity of the matrix of the catalyst that can be used in theprocess according to the invention can advantageously be measured,without this restricting the scope of the invention, by IR tracking ofthe thermodesorption of the pyridine. Generally, the B/L ratio, asdescribed above, of the matrix is encompassed between 0.05 and 1,preferably between 0.05 and 0.7, and very preferably between 0.06 and0.5.

Characteristics of the Substrate

The catalyst that can be used in the process according to the inventionthat is thus obtained is prepared by any technique that is known to oneskilled in the art, starting from a substrate:

1. That comprises a silica-alumina matrix whose characteristics are asfollows:

-   -   The content by mass of silica (SiO₂) is more than 5% by weight        and less than or equal to 95% by weight, preferably encompassed        between 10 and 80% by weight, preferably a silica content of        more than 20% by weight and less than 50% by weight, and even        more preferably more than 20% by weight and less than 40% by        weight,    -   The cationic impurity content is generally less than 0.1% by        weight, preferably less than 0.05% by weight, and even more        preferably less than 0.025% by weight. Cationic impurity content        is defined as the total alkaline content,    -   The anionic impurity content is generally less than 1% by        weight, preferably less than 0.5% by weight, and even more        preferably less than 0.1% by weight.

The silica-alumina that is used in the process according to theinvention is preferably a silica-alumina that is homogeneous on themicrometer scale and in which the content of cationic impurities (forexample, Na⁺) is generally less than 0.1% by weight, preferably lessthan 0.05% by weight and even more preferably less than 0.025% byweight, and the content of anionic impurities (for example SO₄ ²⁻, Cl⁻)is generally less than 1% by weight, preferably less than 0.5% byweight, and even more preferably less than 0.1% by weight.

Thus, any process of synthesis of silica-alumina that is known to oneskilled in the art that leads to a silica-alumina that is homogeneous onthe micrometer scale and in which the cationic impurities (for exampleNa⁺) can be brought to less than 0.1%, preferably to a content of lessthan 0.05% by weight, and even more preferably less than 0.025% byweight, and in which the anionic impurities (for example, SO₄ ²⁻, Cl⁻)can be brought to less than 1% and more preferably less than 0.05% byweight is suitable for preparing substrates that can be used in theprocess according to the invention.

-   -   The mean pore diameter, measured by mercury porosimetry, is        encompassed between 20 and 140 Å, preferably between 40 and 120        Å, and even more preferably between 50 and 100 Å,    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å, to the        total pore volume that is also measured by mercury porosimetry        is generally more than 0.6, preferably more than 0.7, and even        more preferably more than 0.8,    -   Volume V3 that is encompassed in the pores with diameters of        more than D_(mean)+30 Å, measured by mercury porosimetry, is        generally less than 0.1 ml/g, preferably less than 0.06 ml/g,        and even more preferably less than 0.04 ml/g,    -   The ratio between volume V5, measured by mercury porosimetry,        encompassed between D_(mean)−15 Å and D_(mean)+15 Å, to volume        V2, measured by mercury porosimetry, encompassed between        D_(mean)−30 Å and D_(mean)+30 Å, is generally more than 0.6,        preferably more than 0.7, and even more preferably more than        0.8,    -   Volume V6, encompassed in the pores with diameters of more than        D_(mean)+15 Å and measured by mercury porosimetry, is generally        less than 0.2 ml/g, preferably less than 0.1 ml/g and even more        preferably less than 0.05 ml/g,    -   The total pore volume, measured by mercury porosimetry, is        encompassed between 0.1 ml/g and 0.6 ml/g, preferably        encompassed between 0.1 and 0.5 ml/g, and even more preferably        encompassed between 0.1 and 0.4,    -   The total pore volume, measured by nitrogen adsorption, is        encompassed between 0.1 ml/g and 0.6 ml/g, preferably        encompassed between 0.1 and 0.5 ml/g, and even more preferably        encompassed between 0.1 and 0.4,    -   The BET specific surface area is encompassed between 100 and 850        m²/g, preferably encompassed between 150 and 650 m²/g, and more        preferably between 200 and 600 m²/g,    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å, is less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.03 ml/g,    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å, is less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.025 ml/g,    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å, is less than 0.1        ml/g, preferably less than 0.05 ml/g, and even more preferably        less than 0.025 ml/g,    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å, is less than 0.1,        preferably less than 0.05 ml/g, and more preferably less than        0.02 ml/g,    -   The X diffraction diagram is characterized in that it contains        at least the main lines that are characteristic of at least one        of the transition aluminas contained in the group that consists        of the alpha-, rho-, chi-, kappa-, eta-, gamma-, theta- and        delta-aluminas, and preferably characterized in that it contains        at least the main lines that are characteristic of at least one        of the transition aluminas contained in the group that consists        of the gamma-, eta-, theta- and delta-alumina, and more        preferably characterized in that it contains at least the main        lines that are characteristic of the gamma-alumina and        eta-alumina, and even more preferably characterized in that it        contains the peaks at one d encompassed between 1.39 and 1.40 Å        and the peaks at one d encompassed between 1.97 Å and 2.00 Å.

2. And that contains at least one zeolite and at least one mixture ofzeolites.

According to an embodiment of the invention, the zeolite is selectedfrom the FAU group and/or from the group that is formed by the Y zeoliteand the Y zeolites that have undergone a secondary treatment such as, inparticular: USY, VUSY, SDUSY, HMUSY and DAY.

The Y zeolite that is used in the catalysts according to the inventionis at least in part in hydrogen form or acid form (H⁺) or ammonium form(NH₄ ⁺) or cationic form, whereby said cation is selected from the groupthat is formed by the groups IA, IB, IIA, IIB, IIIA, IIIB (including therare earths), Sn, Pb and Si; it is preferably at least in part in H⁺form or it can also be used at least in part in cationic form (asdefined above).

According to another embodiment of the invention, the zeolite is azeolite that is selected from the group that is formed by the mordenite,beta, NU-87, and EU-1 zeolites, preferably the MOR zeolite, used byitself or in a mixture with other zeolites.

In an embodiment of the invention, the matrix comprises at least twosilico-aluminum zones that have Si/Al ratios that are less than orgreater than the overall Si/Al ratio that is determined by Xfluorescence. A matrix according to this invention that has an overallSi/Al ratio that is equal to 0.5 comprises, for example, twosilico-aluminum zones; one of the zones has an Si/Al ratio that isdetermined by TEM to be less than 0.5, and the other zone has an Si/Alratio that is determined by TEM to be between 0.5 and 2.5.

In another embodiment of the invention, the matrix comprises a singlesilico-aluminum zone that has an Si/Al ratio that is equal to theoverall Si/Al ratio that is determined by X fluorescence and is lessthan 2.3.

The packing density of the substrates, after calcination, is more than0.6 g/cm³, preferably more than 0.72 g/cm³, and very preferably morethan 0.8 g/cm³, and even more preferably more than 0.95 g/cm³.

The acidity of the matrix according to the invention can advantageouslybe measured, without this restricting the scope of the invention, by IRtracking of the thermodesorption of the pyridine. Generally, the B/Lratio, as described above, of the matrix according to the invention isencompassed between 0.05 and 1, preferably between 0.05 and 0.7, andvery preferably between 0.06 and 0.5.

Processes of Preparation

The catalysts that can be used in the process according to the inventioncan be prepared according to all the methods that are well known to oneskilled in the art, starting from the substrate that is based on asilico-aluminum matrix and that is based on at least one zeolite.

Matrix

The applicant discovered that the zeolite substrates that are based onsilico-aluminum matrices obtained starting from a mixture at anyarbitrary stage of an alumina compound that is partially soluble in acidmedium with a totally soluble silica compound or with a totally solublecombination of hydrated alumina and silica, shaping followed by ahydrothermal or heat treatment so as to homogenize on the micrometerscale, and even on the nanometer scale, made it possible to obtain aparticularly active catalyst in the hydrocracking processes. Theapplicant defines partially soluble in acid medium as bringing thealumina compound into contact before any addition of totally solublesilica compound or combination with an acid solution, for example,nitric acid or sulfuric acid, causes partial dissolution thereof.

Silica Sources

The silica compounds that are used according to the invention may havebeen selected from the group that is formed by silicic acid, silicicacid sols, water-soluble alkaline silicates, cationic silicon salts, forexample the hydrated sodium metasilicate, Ludox® in ammonia form or inalkaline form, and quaternary ammonium silicates. The silica sol can beprepared according to one of the methods known to one skilled in theart. A decationized orthosilicic acid solution is preferably preparedstarting from a water-soluble alkaline silicate by ion exchange on aresin.

Totally Soluble Silica-Alumina Sources

The totally soluble hydrated silica-aluminas that are used according tothe invention can be prepared by true coprecipitation under controlledstationary operating conditions (pH, concentration, temperature, averagedwell time) by reaction of a basic solution that contains silicon, forexample in the form of sodium silicate, optionally of aluminum, forexample, in sodium aluminate form with an acid solution that contains atleast one aluminum salt, for example aluminum sulfate. At least onecarbonate or else CO₂ optionally can be added to the reaction medium.

The applicant defines true coprecipitation as a process by which atleast one aluminum compound that is totally soluble in basic medium oracid medium as described below, and at least one silicon compound asdescribed below are brought into contact, simultaneously orsequentially, in the presence of at least one precipitating and/orcoprecipitating compound so as to obtain a mixed phase that essentiallyconsists of hydrated silica-alumina that is optionally homogenized byintense stirring, shearing, colloidal grinding or else by a combinationof these unitary operations. For example, these hydrated silica-aluminasmay have been prepared according to the teachings of U.S. Pat. No.2,908,635, U.S. Pat. No. 3,423,332, U.S. Pat. No. 3,433,747, U.S. Pat.No. 3,451,947, U.S. Pat. No. 3,629,152, and U.S. Pat. No. 3,650,988.

The total dissolution of the silica compound or the combination wasevaluated approximately according to the following method. A fixedamount (15 g) of the silica compound or the hydrated combination isintroduced into a medium of preset pH. The concentration of solidconverted per liter of suspension is preferably 0.2 mol per liter. ThepH of the dispersion solution is at least 12, and it can be obtained byuse of an alkaline source. It is preferably advantageous to use NaOH.The mixture is then stirred mechanically by a deflocculant-type turbinestirring mechanism for 30 minutes at 800 rpm. Once the stirring isended, the mixture is centrifuged for 10 minutes at 3000 rpm. The cakeis separated from the supernatant liquid. The solution was filtered on afilter with a porosity of 4 and a diameter of 19 cm. Next, the dryingand then the calcination of the two fractions are initiated at 1000° C.Then, an equal ratio R is defined by dividing the decanted mass by themass of the solid in suspension. Totally soluble is defined as a ratio Rthat is at least more than 0.9.

Alumina Sources

The alumina compounds that are used according to the invention arepartially soluble in acid medium. They are selected completely orpartially from the group of alumina compounds of general formula Al₂O₃,nH₂O. It is possible in particular to use hydrated alumina compoundssuch as: hydrargillite, gibbsite, bayerite, boehmite, pseudo-boehmite,and amorphous or essentially amorphous alumina gels. It is also possibleto use the dehydrated forms of these compounds that consist oftransition aluminas and that comprise at least one of the phasesincluded in the group: rho, chi, eta, gamma, kappa, theta, and delta,which differ essentially by the organization of their crystallinestructure. The alpha-alumina that is commonly called corundum can beincorporated in a small proportion in the substrate according to theinvention.

This partial dissolution property is a desired property of theinvention; it applies to hydrated alumina powders, to sprayed hydratedalumina powders, to dispersions or suspensions of hydrated alumina or toany combination thereof, before any addition of a compound that containssome or all of the silicon.

The partial dissolution of the alumina compound was evaluatedapproximately according to the following method. A specific amount ofthe alumina compound in powder or suspension form is introduced into amedium of preset pH. The mixture is then stirred mechanically. Once thestirring is ended, the mixture is left without stirring for 24 hours.Preferably, the Al₂O₃ solid concentration that is added per liter ofsuspension is 0.5 mol per liter. The pH of the dispersion solution is 2and is obtained by use of HNO₃, HCl, or HClO₄. Preferably, it isadvantageous to use HNO₃. The distribution of sedimented and dissolvedfractions was followed by metering of aluminum by UV absorption. Thesupernatants were ultrafiltered (polyether sulfone membrane, MilliporeNMWL: 30,000) and digested in concentrated acid. The amount of aluminumin the supernatant corresponds to the non-sedimented alumina compoundand the dissolved aluminum and the fraction that is ultrafiltered withdissolved aluminum only. The amount of sedimented particles is derivedfrom the theoretical concentration of aluminum in the dispersion (byconsidering that all of the solid that is introduced is dispersed) andamounts of boehmite actually dispersed and aluminum in solution. Thealumina precursors that are used according to this invention aretherefore distinguished from those that are used in the case of trueco-precipitations that are entirely soluble in acid medium: cationicalumina salts, for example aluminum nitrate. The methods that are partof the invention are distinguished from true co-precipitations becauseone of the elements, in this case the aluminum compound, is partiallysoluble.

To use the alumina, any alumina compound of general formula Al₂O₃, nH₂Ocan be used. Its specific surface area is between 150 and 600 m²/g. Itis possible in particular to use hydrated alumina compounds, such as:hydrargillite, gibbsite, bayerite, boehmite, pseudo-boehmite andamorphous or essentially amorphous alumina gels. It is also possible touse the dehydrated forms of these compounds that consist of transitionaluminas and that comprise at least one of the phases included in thegroup: rho, chi, eta, gamma, kappa, theta, delta and alpha, which differessentially by the organization of their crystalline structure. Duringheat treatments, these different forms are liable to evolve amongthemselves, according to a complex relationship that depends on thetreatment operating conditions. It is also possible to use thealpha-alumina that is commonly called corundum in measured proportions.

The aluminum hydrate Al₂O₃, nH₂0 that is more preferably used isboehmite, pseudo-boehmite and the amorphous or essentially amorphousalumina gels. A mixture of these products under any arbitrarycombination can also be used.

Boehmite is generally described as an aluminum monohydrate of formulaAl₂O₃, nH₂O that in reality includes a broad continuum of materials withvariable degrees of hydration and organization with more or lesswell-defined boundaries: the most hydrated gelatinous boehmite, with nable to be more than 2, the pseudo-boehmite or the microcrystallineboehmite with n encompassed between 1 and 2, then crystalline boehmite,and finally boehmite that is well crystallized with large crystals withn close to 1. The morphology of aluminum monohydrate can vary withinbroad limits between these two acicular or prismatic end forms. Anentire set of variable forms can be used between these two forms: chain,boats, interlaced platelets.

The preparation and/or the shaping of the aluminum hydrate thus canconstitute the first stage of the preparation of these catalysts. Manypatents relate to the preparation and/or the shaping oftransition-alumina-based substrates that are obtained from aluminummonohydrate: U.S. Pat. No. 3,520,654; U.S. Pat. No. 3,630,670; U.S. Pat.No. 3,864,461; U.S. Pat. No. 4,154,812; U.S. Pat. No. 4,313,923; DE-A-3243 193; and U.S. Pat. No. 4,371,513.

Relatively pure aluminum hydrates can be used in the form of amorphouspowder or crystallized powder or crystallized powder that contains anamorphous portion. The aluminum hydrate can also be introduced in theform of aqueous suspensions or dispersions. The aqueous suspensions ordispersions of aluminum hydrate that are used according to the inventionmay have the ability to gel or solidify. The aqueous dispersions orsuspensions can also be obtained, as is well known to one skilled in theart, by peptization in water or water that is acidified with aluminumhydrates.

The dispersion of aluminum hydrate can be carried out by any processthat is known to one skilled in the art: in a “batch” reactor, acontinuous mixer, a mixing machine, or a colloidal mill. Such mixing canbe also be carried out in a piston flow reactor and, in particular, in astatic mixer. The Lightnin reactors can be cited.

In addition, it is also possible to use as an alumina source an aluminathat has been subjected in advance to a treatment that can improve itsdegree of dispersion. By way of example, it will be possible to improvethe dispersion of the alumina source by a preliminary homogenizationtreatment. For homogenization, it is possible to use at least one of thehomogenization treatments described in the following text.

The aqueous dispersions or suspensions of alumina that can be used are,in particular, the aqueous suspensions or dispersions of fine orultra-fine boehmites that consist of particles that have dimensions inthe colloidal range.

Fine or ultra-fine boehmites that are used according to this inventionmay have been obtained in particular according to French Patents FR-B-1261 182 and FR-B-1 381 282 or in European Patent Application EP-A-15196.

It is also possible to use the aqueous suspensions or dispersions thatare obtained from pseudo-boehmite, amorphous alumina gels, aluminumhydroxide gels or ultra-fine hydrargillite gels.

Aluminum monohydrate can be purchased from among a variety of commercialsources of alumina, such as, in particular, PURAL®, CATAPAL®, DISPERAL®,and DISPAL®, that are marketed by the SASOL Company or else HIQ® that ismarketed by ALCOA, or according to the methods that are known to oneskilled in the art: it can be prepared by partial dehydration ofaluminum trihydrate by conventional methods or it can be prepared byprecipitation. When these aluminas are presented in the form of a gel,they are peptized by water or an acidified solution. In theprecipitation, the acid source can be selected, for example, from amongat least one of the following compounds: aluminum chloride, aluminumsulfate, or aluminum nitrate. The basic aluminum source can be selectedfrom among the basic aluminum salts such as sodium aluminate andpotassium aluminate.

As precipitating agents, sodium hydroxide, sodium carbonate, potassiumand ammonia can be used. The precipitating agents are selected such thatthe alumina source according to this invention and these agents areprecipitated together.

According to the acidic or basic nature of the aluminum-based startingcompound, the aluminum hydrate is precipitated with the aid of a base oran acid that is selected from among, for example, hydrochloric acid,sulfuric acid, sodium or a basic or acidic compound of the aluminum suchas those cited above. The two reagents can be aluminum sulfate andsodium aluminate. For an example of a preparation of aluminumalpha-monohydrate that uses aluminum sulfate and sodium aluminate, it ispossible to refer in particular to U.S. Pat. No. 4,154,812.

In particular, pseudo-boehmite may have been prepared according to theprocess that is described in U.S. Pat. No. 3,630,670 by reaction of analkaline aluminate solution with a mineral acid solution. Thepseudo-boehmite may have been prepared in particular according to theprocess that is described in U.S. Pat. No. 3,630,670 by reaction of analkaline aluminate solution with a solution of a mineral acid. It mayalso have been prepared as described in French Patent FR-B-1 357 830.

In particular, the amorphous alumina gels may have been preparedaccording to the processes that are described in the article “AlcoaPaper No. 19 (1972), pages 9 to 12” and in particular by reaction ofacid aluminate or an aluminum salt or by hydrolysis of aluminumalcoholates or by hydrolysis of basic aluminum salts.

The aluminum hydroxide gels can be in particular those that have beenprepared according to the processes that are described in U.S. Pat. No.3,268,295 and U.S. Pat. No. 3,245,919.

In particular, the aluminum hydroxide gels may be those that areprepared according to the processes that are described in PatentApplication WO-A-00/01 617 by mixing an aluminum acid source and a baseor an aluminum basic source and an acid so as to precipitate an aluminamonohydrate, whereby the following stages are:

2. Development

3. Filtration

4. Washing, and

5. Drying,

processes that are characterized in that the mixing of stage one iscarried out without retromixing.

The ultrafine hydrargillite may have been prepared in particularaccording to the process that is described in U.S. Pat. No. 1,371,808 byevolving toward a temperature encompassed between ambient temperatureand 60° C. for alumina gels in cake form and that contain 0.1 monovalentacid ion relative to the alumina that is counted by Al₂O₃ molecules.

It is also possible to use ultra-pure aqueous suspensions or dispersionsof boehmite or pseudo-boehmite that are prepared according to a processin which the reaction of an alkaline aluminate is carried out with thecarbonic anhydride to form an amorphous aluminum hydroxycarbonateprecipitate, the precipitate that is obtained by filtration isseparated, and then the latter is washed (the process is described inparticular in U.S. Pat. No. 3,268,295).

Then,

-   -   a) In a first stage, the precipitate that is washed with        amorphous aluminum hydroxycarbonate is mixed with an acid        solution, a base or a salt or mixtures thereof; this mixing is        carried out by pouring the solution over the hydroxycarbonate,        whereby the pH of the thus constituted medium is less than 11,    -   b) In a second stage, the thus constituted reaction medium is        heated to a temperature of less than 90° C. for a period of at        least 5 minutes, and    -   c) In a third stage, the medium that results from the second        stage is heated to a temperature of between 90° C. and 250° C.

The boehmite and pseudo-boehmite dispersions or suspensions that areobtained according to this process exhibit an alkaline content of lessthan 0.005% that is expressed in the form of a ratio by weight ofalkaline metal oxide/Al₂O₃.

When it is desired to produce very pure catalyst substrates, ultra-pureboehmite or pseudo-boehmite suspensions or dispersions that have beenobtained according to the process that was described above, or thealuminum hydroxide gels that were prepared starting from the hydrolysisof aluminum alcoholates according to a process of the type that isdescribed in U.S. Pat. No. 2,892,858 are preferably used.

In summary, the production process that leads to such boehmite-typealuminum hydroxide gels obtained as a by-product in the production ofalcohol by hydrolysis of an alcoholate or alkoxide of aluminum (Zieglersynthesis) is described. The Ziegler alcohol synthesis reactions aredescribed in particular in U.S. Pat. No. 8,928,58. According to thisprocess, first triethyl aluminum is prepared starting from aluminum,hydrogen and ethylene, whereby the reaction is carried out in two stageswith partial recycling of triethyl aluminum.

Ethylene is added into the polymerization stage, and the product that isobtained is then oxidized into aluminum alcoholate, whereby the alcoholsare obtained by hydrolysis.

The aluminum hydroxide gels can also be those that were preparedaccording to the processes described in U.S. Pat. No. 4,676,928 and U.S.Pat. No. 6,030,599.

The hydrated alumina that is obtained as a by-product of the Zieglerreaction is described in particular in a report of the CONOCO Companydated Jan. 19, 1971.

The size of the alumina particles that constitute the alumina source canvary within broad limits. It is generally between 1 and 100 microns.

Methods for Preparation of the Matrix

The matrix can advantageously be prepared by one of the methodsdescribed below.

By way of example, a method of preparation of a silica-alumina that ispart of the invention consists in preparing, starting from awater-soluble alkaline silicate, an orthosilicic acid solution (H₂SiO₄,H₂O) that is decationized by ion exchange, then in simultaneously addingit to a cationic aluminum salt in solution, for example, nitrate, and toammonia under controlled operating conditions; or else adding theorthosilicic acid solution to the cationic aluminum salt in solution andcoprecipitating the solution that is obtained by ammonia undercontrolled operating conditions leading to a homogeneous product. Thissilica-alumina hydrogel is mixed with an aluminum hydrate powder orsuspension. After filtering and washing, drying with shaping thencalcination, preferably in air, in a rotary kiln, at a high temperatureand for an adequate period to promote interactions between the aluminaand the silica, generally at least two hours, a matrix that fulfills thecharacteristics of the invention is obtained.

Another method for preparation of silica-alumina according to theinvention consists in precipitating the alumina hydrate as describedabove, in filtering it and washing it, then in mixing it with aqueousorthosilicic acid so as to obtain a suspension, which is thoroughlyhomogenized by vigorous stirring and shearing. An ULTRATURRAX® turbineor else a STARO® turbine can be used, or else a colloidal mill, forexample a STARO® colloidal mill. The homogeneous suspension is thendried by spraying as described above, then calcined between 500 and1200° C. for at least three hours: a silica-alumina matrix that can beused in the process according to the invention is obtained.

Another method that is part of the invention consists in preparing, asdescribed above, a decationized solution of orthosilicic acid then inadding it simultaneously or consecutively to an alumina compound, forexample an aluminum hydrate in powder form or in acidified suspensionform. To increase the diameter of the pores of the final silica-aluminasubstrate, at least one basic compound can optionally be added to thereaction medium. After an intense homogenization of the suspension bystirring, optional adjustment by filtration of the content of drymaterial then optionally rehomogenization, the product is dried withsimultaneous or consecutive shaping, then calcined as described above.

Another method that is also part of the invention consists in preparingan aqueous alumina suspension or dispersion, for example an aluminummonohydrate, then in adding it simultaneously or consecutively to asilica compound, for example a sodium silicate. To increase the diameterof the pores of the final silica-alumina matrix, at least one basiccompound can optionally be added to the reaction medium. The matrix isobtained by filtration and washing, optionally washing by an ammoniasolution to extract the residual sodium by ion exchange, drying withsimultaneous or consecutive shaping. After drying with shaping, thencalcination as described above, a substrate that fulfills thecharacteristics of the invention is obtained. The size of the aluminaparticles used is preferably between 1 and 100 microns to obtain goodhomogenization of the silica-alumina substrate according to theinvention.

To increase the diameter of the mesopores of the silica-alumina matrix,it may be particularly advantageous, as U.S. Pat. No. 4,066,574 teachesit, to prepare an aqueous alumina suspension or dispersion, for example,an aluminum monohydrate, and then to neutralize by a basic solution, forexample ammonia, then to add it simultaneously or consecutively to asilica compound, for example a decationized orthosilicic acid solution.After an intensive homogenization of the suspension by intense stirring,optional adjustment by filtration of the dry material content thenrehomogenization, the product is dried with simultaneous or consecutiveshaping, then calcined as described above. This method is also part ofthe methods that are used according to the invention.

In the specification of the above-mentioned methods, homogenization isused to describe putting back into solution a product that contains asolid fraction, for example a suspension, a powder, a filteredprecipitate, then its dispersion under intense stirring. Thehomogenization of a dispersion is a process that is well known to oneskilled in the art. Said homogenization can be carried out by anyprocess that is known to one skilled in the art: by way of example in abatch reactor, a continuous mixer, or a mixing machine. Such a mixingcan be carried out in a piston flow reactor and in particular in astatic reactor. The Lightnin reactors can be cited. An ULTRATURRAX®turbine or else a STARO® turbine can be used, or else a colloidal mill,for example a STARO® colloidal mill. The commercial colloidal mills IKA®can also be used.

In all of the above-mentioned methods, it may optionally be desirable toadd, during any arbitrary stage of the preparation, a minor proportionof at least one stabilizing element that is selected from the group thatis formed by zirconia and titanium. The stabilizing element ispreferably added in the form of a soluble salt.

The acidity of the matrix according to the invention can advantageouslybe measured, without this restricting the scope of the invention, by IRtracking of the thermodesorption of the pyridine. Generally, the B/Lratio of the matrix according to the invention is encompassed between0.05 and 1, preferably between 0.05 and 0.7, and very preferably between0.06 and 0.5.

Zeolite

According to an embodiment of the invention, but without therebyrestricting the scope of the invention, the Y zeolites with faujasitestructure (“Zeolite Molecular Sieves Structure Chemistry and Uses,” D.W. Breck, J. Wiley and Sons, 1973) that can be in hydrogen form orpartially exchanged with metallic cations, for example with the aid ofcations of alkaline-earth metals and/or rare earths of atomic numbers 57to 71 inclusive, are used. The Y zeolites that have undergone asecondary treatment are also part of the invention. Secondary treatmentis defined as in particular the treatments described in: “Hydrocracking,Science and Technology,” J. Scherzer, A. J. Gruia, 1996 or in R. J.Beyerlein. The Y zeolites, for example, are prepared according to thetechniques that are generally used by the dealuminification.

The Y zeolites that are used in general in the catalysts are produced bymodification of the Na—Y zeolite that is available commercially. Thismodification makes it possible to end in zeolites that are said to bestabilized, ultra-stabilized (USY), very ultrastabilized (VUSY) or elsedealuminified (SDUSY). This designation is common in the literature, butit does not thereby restrict the characteristics of the zeolites of thisinvention with such a name. This modification is carried out by thecombination of three types of operations that are known to one skilledin the art: hydrothermal treatment, ion exchange and acid attack. Thehydrothermal treatment is perfectly defined by the conjonction ofoperating variables that are temperature, duration, total pressure andpartial pressure of water vapor. The purpose of this treatment is toextract aluminum atoms from the silico-aluminum framework of thezeolite. The consequence of this treatment is an increase of theSiO₂/Al₂O₃ framework molar ratio and a reduction of the parameter of thecrystalline mesh.

The ion exchange generally takes place by the immersion of the zeoliteinto an aqueous solution that contains ions that can be fixed to thecationic exchange sites of the zeolite. The sodium cations that arepresent in the zeolite are thus removed after crystallization.

The acid attack operation consists in bringing the zeolite into contactwith an aqueous solution of a mineral acid. The severity of the acidattack is adjusted by the acid concentration, the duration and thetemperature. Carried out on a hydrothermally-treated zeolite, thistreatment has the effect of eliminating the aluminum radicals that areextracted from the framework and that clog the micropores of the solid.

Furthermore, a particular hydrothermal treatment as described in U.S.Pat. No. 5,601,798 has the effect of increasing the mesopores of the Y,USY, VUSY and SDUSY zeolites, which zeolites are particularlyadvantageous in combination with the amorphous matrix that is describedabove.

Various Y zeolites can advantageously be used.

According to a preferred embodiment of the invention, a particularlyadvantageous H—Y acid zeolite is characterized by variousspecifications: an overall SiO₂/Al₂O₃ molar ratio of between about 6 and140 and preferably between about 12 and 100: a sodium content of lessthan 0.15% by weight determined on the zeolite that is calcined at 1100°C.; a crystalline parameter with elementary mesh encompassed between24.58×10⁻¹⁰ m and 24.15×10⁻¹⁰ m and preferably between 24.38×10⁻¹⁰ m and24.20×10⁻¹⁰ m; a CNa capacity for sodium ion uptake, expressed by gramof Na per 100 grams of modified zeolite that is neutralized, thencalcined, more than about 0.85; a specific surface area that isdetermined by the B.E.T. method of more than about 400 m²/g andpreferably more than 550 m²/g, a water vapor adsorption capacity at 25°C. for a partial pressure of 2.6 torrs (or 34.6 MPa), more than about6%, and advantageously, the zeolite exhibits a pore distribution,determined by nitrogen physisorption, comprising between 5 and 45% andpreferably between 5 and 40% of the total pore volume of the zeolitethat is contained in pores with diameters of between 20×10⁻¹⁰ m and80×10⁻¹⁰ m, and between 5 and 45% and preferably between 5 and 40% ofthe total pore volume of the zeolite that is contained in pores withdiameters of more than 80×10⁻¹⁰ m and generally less than 1000×10⁻¹⁰ m,whereby the remainder of the pore volume is contained in the pores withdiameters of less than 20×10⁻¹⁰ m.

A preferred catalyst that uses this type of zeolite contains asilico-aluminum matrix, at least one Y zeolite that is dealuminified andthat has a crystalline paramter encompassed between 2.415 nm and 2.455nm, preferably between 2.420 and 2.438 nm, an overall SiO₂/Al₂O₃ molarratio of more than 8, a content of cations of alkaline-earth metals oralkalines and/or cations of rare earths, such that the (n×M^(n+))/Alatomic ratio is less than 0.8, preferably less than 0.5 or else 0.1, aspecific surface area that is determined by the B.E.T. method of morethan 400 m²/g, preferably more than 550 m²/g, and a water adsorptioncapacity at 25° C. for a P/Po value of 0.2, more than 6% by weight,whereby said catalyst also comprises at least one hydro-dehydrogenatingmetal, and silicon that is deposited on the catalyst.

In an advantageous embodiment according to the invention, a partiallyamorphous Y zeolite is used.

Partially amorphous Y zeolite is defined as a solid that exhibits:

-   -   i) A peak rate that is less than 0.40, preferably less than        about 0.30, and    -   ii) A crystalline fraction that is expressed relative to a        reference Y zeolite in sodic form (Na) that is less than about        60%, preferably less than about 50%, and determined by x-ray        diffraction.

The partially amorphous, solid Y zeolites that fall within thecomposition of the catalyst according to the invention preferablyexhibit at least one (or preferably all) of the other characteristicsbelow:

-   -   iii) An overall Si/Al ratio of more than 15, preferably more        than 20 and less than 150,    -   iv) An Si/Al^(IV) framework ratio that is more than or equal to        the overall Si/Al ratio,    -   v) A pore volume that is at least equal to 0.20 ml/g of solid of        which a fraction, encompassed between 8% and 50%, consists of        pores that have diameters of at least 5 nm (nanometer), or 50 Å        and    -   vi) a specific surface area of 210-800 m²/g, preferably 250-750        m²/g, and advantageously 300-600 m²/g.

The peak rate of a standard USY zeolite is 0.45 to 0.55; its crystallinefraction relative to a perfectly crystallized NaY is 80 to 95%. The peakrate of the solid that is the object of this description is less than0.4 and preferably less than 0.35. Its crystalline fracion is thereforeless than 70%, preferably less than 60%.

The partially amorphous zeolites are prepared according to thetechniques that are generally used for dealuminification, starting fromY zeolites that are available commercially, i.e., that generally exhibithigh crystallinities (at least 80%). More generally, it will be possibleto start from zeolites that have a crystalline fraction of at least 60%,or at least 70%.

The Y zeolites that are generally used in the catalysts are produced bymodification of Na—Y zeolites that are available commercially. Thismodification makes it possible to end in so-called stabilized,ultra-stabilized or else dealuminified zeolites. This modification iscarried out by at least one of the dealuminification techniques, and,for example, the hydrothermal treatment, the acid attack. Thismodification is preferably carried out by combination of three types ofoperations that are known to one skilled in the art: the hydrothermaltreatment, the ion exchange and the acid attack.

Another particularly advantageous zeolite for the catalyst that can beused in the process according to this invention is a globallynon-dealuminified and very acidic zeolite.

Globally non-dealuminified zeolite is defined as a Y zeolite (FAUstructural type, faujasite) according to the nomenclature developed in“Atlas of Zeolite Structure Types,” W. M. Meier, D. H. Olson and Ch.Baerlocher, 4^(th) Revised Edition, 1996, Elsevier. The crystallineparameter of this zeolite may have reduced by extraction aluminums ofthe structure or framework during the preparation, but the overallSiO₂/Al₂O₃ ratio has not changed because the aluminums have not beenextracted chemically. Such a globally non-dealuminified zeolitetherefore has a silicon and aluminum composition that is expressed bythe overall SiO₂/Al₂O₃ ratio that is equivalent to the startingnon-dealuminified Y zeolite. The values of the parameters (SiO₂/Al₂O₃ratio and crystalline parameter) are provided below. This globallynon-dealuminified Y zeolite can be either in hydrogen form or at leastpartially exchanged with metallic cations, for example with the aid ofalkaline-earth metal cations and/or rare earth metal cations of atomicnumbers 57 to 71 inclusive. A zeolite that is lacking in rare earths andalkaline earths, likewise for the catalyst, will be preferred.

The nonglobally dealuminified Y zeolite generally exhibits a crystallineparameter of more than 2.438 nm, an overall SiO₂/Al₂O₃ ratio of lessthan 8, an SiO₂/Al₂O₃ framework molar ratio of less than 21 and morethan the overall SiO₂/Al₂O₃ ratio. An advantageous catalyst combinesthis zeolite with a phosphorus-doped matrix.

The globally non-dealuminified zeolite can be obtained by any treatmentthat does not extract aluminum from the sample, such as, for example,treatment with water vapor, treatment by SiCl₄.

In another preferred embodiment of the invention, the substratecomprises a zeolite as described in U.S. Pat. No. 5,601,978. Thesezeolites are described in particular in column 30, lines 48-64. Theirmesopore volume is in particular more than 0.202 cm³/g for a meshparameter encompassed between 24.5 Å and 24.6 Å and more than 0.313cm³/g for a mesh parameter encompassed between 24.3 and 24.5 Å.

According to another embodiment of the invention, the zeolite is azeolite that is selected from the group that is formed by the mordenite,beta, NU-87 and EU-1 zeolites, preferably the MOR zeolite, used byitself or in a mixture with other zeolites.

The preparation and the treatment or treatments as well as the shapingof the zeolite can thus constitute one stage of the preparation of thesecatalysts.

The introduction of the zeolite can be done by any technique that isknown to one skilled in the art during the preparation of the matrix orduring the shaping of the substrate.

The total content by weight of zeolite in the substrate is encompassedbetween 0.1% and 99%, advantageously between 1% and 90%, preferablybetween 20% and 80%, even more preferably between 30 and 60%.

Preparation of the Catalyst

The catalysts according to the invention can be prepared according toall of the methods that are well known to one skilled in the artstarting from substrates that are prepared as described above.

The zeolite can be introduced according to any method that is known toone skilled in the art at any stage of the preparation of the substrateor catalyst.

A preferred process for the preparation of the catalyst according tothis invention comprises the following stages:

According to a preferred method of preparation, the zeolite can beintroduced during the synthesis of the precursors of the matrix. Thezeolite can be, for example, without this being limiting, in the form ofpowder, ground powder, suspension, or suspension that has undergone adeagglomeration treatment. Thus, for example, the zeolite can be putinto a suspension that may or may not be acidified at a concentrationthat is adjusted to the final content of zeolite targeted in thesubstrate. This suspension that is commonly called a slip is then mixedwith the precursors of the matrix at any stage of its synthesis asdescribed above.

According to another preferred method of preparation, the zeolite canalso be introduced during the shaping of the substrate with the elementsthat constitute the matrix with optionally at least one binder. Thezeolite can be, without this being limiting, in the form of powder,ground powder, suspension or suspension that has undergone adeagglomeration treatment.

The preparation and the treatment or treatments as well as the shapingof the zeolite thus can constitute one stage of the preparation of thesecatalysts.

The possible hydro-dehydrogenating element can be introduced at anystage of the preparation, preferably during the mixing, or verypreferably after shaping. The shaping is followed by a calcination, thehydrogenating element can also be introduced before or after thiscalcination. The preparation generally ends by a calcination at atemperature of 250 to 600° C. Another of the preferred methods accordingto this invention consists in shaping the substrate after the latter ismixed, then passage of the thus obtained paste through a die to formextrudates with diameters of between 0.4 and 4 mm. The hydrogenatingfunction can then be introduced in part only or in full at the time ofmixing. It can also be introduced by one or more ion exchange operationson the calcined substrate that consists of at least one silica-aluminathat is optionally shaped with a binder and at least one zeolite withthe aid of solutions that contain the precursor salts of the selectedmetals.

The substrate is preferably impregnated by an aqueous solution. Theimpregnation of the substrate is preferably carried out by the so-called“dry” impregnation method that is well known to one skilled in the art.The impregnation can be carried out in a single stage by a solution thatcontains all the constituent elements of the final catalyst.

The catalyst that can be used in the process of this invention cantherefore contain at least one noble element of group VIII such asruthenium, rhodium, palladium, osmium, iridium or platinum. Among thenoble metals of group VIII, it is preferred to use a metal that isselected from the group that is formed by platinum, palladium andruthenium. A preferred combination of noble elements of group VIII forthe catalyst that can be used in the process of this invention is theplatinum-palladium combination.

The halogenated elements can be introduced into the catalyst at anylevel of the preparation and according to any technique that is known toone skilled in the art. The halogenated compounds are preferably addedwith the aid of an aqueous solution that is prepared from correspondingmineral acids, for example HF or HCl (dry impregnation, by excess orco-mixing). The use of ammonium fluoride/ammonium chloride (NH₄F, NH₄HF₂or NH₄Cl) can also be considered, whereby the dry impregnation of thesubstrates by this type of compound is furthermore the most used methodin the scientific literature in the field.

The breakdown of the organofluorine compounds and/or organochlorinecompounds in the catalyst is a method that may also be suitable in theinvention. This makes it possible to prevent the use of hydrofluoricacid solutions, now regulated.

The noble metals of group VIII of the catalyst of this invention can bepresent in full or partially in metallic form and/or oxide and/orsulfide form.

The sources of noble elements of group VIII that can be used are wellknown to one skilled in the art. The halides, for example the chlorides,the nitrates, the acids such as chloroplatinic acid, the oxychloridessuch as the ammoniacal ruthenium oxychloride, or the amines, will beused.

Shaping of the Substrates and Catalysts

The substrate can be shaped by any technique that is known to oneskilled in the art. The shaping can be carried out, for example, byextrusion, by pelletizing, by the drop (“oil-drop”) coagulation method,by turntable granulation or by any other method that is well known toone skilled in the art.

The shaping can also be carried out in the presence of variouscomponents of the catalyst and extrusion of the mineral paste that isobtained, by pelletizing, shaping in the form of balls with a rotatinggroove or with a drum, drop coagulation, “oil-drop,” “oil-up” or anyother known process for agglomeration of a powder that contains aluminaand optionally other ingredients that are selected from among those thatare mentioned above.

The catalysts that are used according to the invention have the shape ofspheres or extrudates. It is advantageous, however, that the catalystcomes in the form of extrudates with a diameter of between 0.5 and 5 mmand more particularly between 0.7 and 2.5 mm. The shapes are cylindrical(which may or may not be hollow), twisted cylindrical, multilobar (2, 3,4 or 5 lobes, for example), and rings. The cylindrical shape ispreferably used, but any other shape may be used.

The packing density of substrates, after calcination, is more than 0.6g/cm³, preferably more than 0.72 g/cm³, very preferably more than 0.8g/cm³, and even more preferably more than 0.95 g/cm³.

The packing density of the catalysts is more than 0.65 g/cm³, preferablymore than 0.8 g/cm³, very preferably more than 0.95 g/cm³ and even morepreferably more than 1.05 g/cm³.

Furthermore, these substrates that are used according to this inventionmay have been treated, as is well known to one skilled in the art, byadditives to facilitate the shaping and/or to improve the finalmechanical properties of the silico-aluminum matrix-based substrates. Byway of example of additives, it is possible to cite in particularcellulose, carboxymethyl-cellulose, carboxy-ethyl-cellulose, tall oil,xanthan gums, surfactants, flocculent agents such as polyacrylamides,carbon black, starches, stearic acid, polyacrylic alcohol, polyvinylalcohol, biopolymers, glucose, polyethylene glycols, etc.

The adjustment of the porosity that is characteristic of the substratesof the invention is carried out partially during this shaping stage ofthe substrate particles.

The shaping can be carried out by using techniques for shaping thecatalysts, known to one skilled in the art, such as, for example:extrusion, sugar-coating, spray-drying or else pelletizing.

It is possible to add or to remove water to adjust the viscosity of thepaste that is to be extruded. This stage can be carried out at any stageof the mixing stage.

To adjust the content of solid material of the paste that is to beextruded so as to make it extrudable, it is also possible to add acompound that is solid for the most part and preferably an oxide or ahydrate. A hydrate will preferably be used, and even more preferably, analuminum hydrate will be used. The fire loss of this hydrate will bemore than 15%.

The acid content added in the mixing before the shaping is less than30%, preferably between 0.5 and 20% by weight of the anhydrous silicaand alumina mass that is engaged in the synthesis.

The extrusion can be carried out by any conventional tool, availablecommercially. The paste that is obtained from mixing is extruded througha dye, for example with the aid of a piston or a single- ordouble-extrusion screw. This extrusion stage can be carried out by anymethod that is known to one skilled in the art.

The substrate extrudates of the invention generally have a resistance tocrushing of at least 70 N/cm and preferably of greater than or equal to100 N/cm.

Calcination of the Substrate

The drying is carried out by any technique that is known to one skilledin the art.

To obtain the substrate of this invention, it is preferable to calcinatepreferably in the presence of molecular oxygen, for example by carryingout a flushing with air, at a temperature that is less than or equal to1100° C. At least one calcination can be carried out after any arbitrarystage of the preparation. This treatment can be performed, for example,in a flushed bed, in a swept bed or in static atmosphere. For example,the furnace that is used can be a rotary kiln or a vertical furnace withradial flushed layers. The calcination conditions: the temperature andduration depend mainly on the maximum temperature of use of thecatalyst. The preferred conditions of calcination are between more thanone hour at 200° C. to less than one hour at 1100° C. The calcinationcan be performed in the presence of water vapor. The final calcinationoptionally can be carried out in the presence of an acidic or basicvapor. For example, the calcination can be carried out under partialpressure of ammonia.

Post-Synthesis Treatments

Post-synthesis treatments can be carried out so as to improve theproperties of the substrate, in particular its homogeneity as definedabove.

According to the invention, the substrate thus can optionally besubjected to a hydrothermal treatment in a confined atmosphere.Hydrothermal treatment in a confined atmosphere is defined as atreatment by passage with an autoclave in the presence of water under atemperature that is higher than the ambient temperature.

During this hydrothermal treatment, it is possible to treat the shapedsilica-alumina or the substrate (matrix+zeolite) in different ways.Thus, it is possible to impregnate the silica-alumina or the substratewith acid, prior to its passage to the autoclave, whereby autoclaving ofthe silica-alumina is done either in vapor phase or in liquid phase,whereby this vapor phase or liquid phase of the autoclave may or may notbe acid. This impregnation, prior to the autoclaving, may or may not beacid. This impregnation, prior to the autoclaving, can be carried out inthe dry state or by immersion of the silica-alumina in an acidic aqueoussolution. Dry impregnation is defined as bringing the alumina intocontact with a solution volume that is less than or equal to the totalpore volume of the treated alumina. The impregnation is preferablycarried out in the dry state.

The autoclave is preferably a rotary-basket autoclave such as the onethat is defined in Patent Application EP-A-0 387 109.

The temperature during the autoclaving can be between 100 and 250° C.for a period of time of between 30 minutes and 3 hours.

Process for the Production of Phenylalkanes and Embodiments

The invention relates to a process for the production of at least onecompound that is selected from among the 2-, 3-, 4-, 5-, and6-phenylalkanes by alkylation of an aromatic compound (preferablybenzene) by means of a feedstock that contains at least one olefin thatcomprises at least 9 carbon atoms per molecule, in the presence of acatalyst that comprises at least one substrate that is based on at leastone zeolite or zeolite mixture and that is based on a silica-aluminabase, whereby said matrix contains an amount of more than 5% by weightand less than or equal to 95% by weight of silica (SiO₂) and thatexhibits the following characteristics:

-   -   A mean pore diameter, measured by mercury porosimetry,        encompassed between 20 and 140 Å,    -   A total pore volume, measured by mercury porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g,    -   A total pore volume, measured by nitrogen porosimetry,        encompassed between 0.1 ml/g and 0.6 ml/g,    -   A BET specific surface area encompassed between 100 and 850        m²/g,    -   A packing density after calcination of more than 0.65 g/cm³,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å, of less than 0.1        ml/g,    -   A pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å, of less than 0.1        ml/g, preferably less than 0.05 ml/g, and very preferably less        than 0.02 ml/g,    -   An X diffraction diagram that contains at least the main lines        that are characteristic of at least one of the transition        aluminas contained in the group that consists of the alpha-,        rho-, chi-, eta-, gamma-, kappa-, theta- and delta-aluminas,    -   Preferably a pore distribution, such that the ratio between        volume V2, measured by mercury porosimetry, encompassed between        D_(mean)−30 Å and D_(mean)+30 Å, to the total mercury volume is        more than 0.6, such that volume V3, measured by mercury        porosimetry, encompassed in the pores with diameters of more        than D_(mean)+30 Å, is less than 0.1 ml/g, and such that volume        V6, measured by mercury porosimetry, encompassed in the pores        with diameters of more than D_(mean)+15 Å, is less than 0.2        ml/g,        whereby said process is carried out at a temperature of between        30 and 400° C., a pressure of between 0.1 and 10 MPa, an hourly        volumetric flow rate of 0.50 to 200 h⁻¹, and an aromatic        compound/olefin molar ratio of between 1:1 and 50:1.

The feedstock that contains at least one olefin (olefinic feedstock)preferably consists of for the most part paraffins.

In an embodiment of the process of the invention, the reactions ofalkylation and transalkylation take place together in the same reactionzone (i.e., in the same reactor in the presence of the same catalyst).

In this variant of the process according to the invention, in a reactionzone, the aromatic compound is preferably reacted with a feedstock thatcontains at least one olefin (olefinic feedstock), for example a linearolefin, upon contact with a catalyst that comprises a silica-aluminathat has the characteristics defined previously (alkylation reaction),then the product that is obtained is fractionated so as to collectseparately a first fraction that contains unconverted aromatic compound,a second fraction that contains at least one olefin, for example linear,initially present in the feedstock (unconverted), a third fraction thatcontains the 2-, 3-, 4-, 5- and 6-phenylalkanes, and a fourth fractionthat contains at least one poly-alkylaromatic compound (orpoly-alkylaromatic fraction), whereby the latter is then most often atleast partially recycled to said reaction zone where it reacts with thearomatic compound upon contact with said catalyst, so as to be at leastpartially transalkylated (transalkylation reaction), and a mixture of2-, 3-, 4-, 5- and 6-phenylalkanes is collected.

The first fraction that contains the unconverted aromatic compound ispreferably at least partially recycled to said reaction zone. Likewise,the second fraction that contains at least one unconverted, preferablylinear, olefin is preferably at least partially recycled to saidreaction zone.

The recycled portion of the fourth fraction that for the most partcontains in general at least one dialkylaromatic compound is preferablyessentially free of heavy alkylaromatic compounds, which can beeliminated by fractionation.

The aromatic compound that is used in this variant of the processaccording to the invention is preferably benzene.

The alkylation reaction of the process according to this invention canbe conducted in the presence of hydrogen, in particular in the casewhere the catalyst contains a noble element of group VIII.

The process according to this invention can be carried out, for thealkylation stage, at a temperature of between 30 and 400° C., under apressure of 0.1 to 10 MPa, with a liquid hydrocarbon flow rate (hourlyvolumetric flow rate) of about 0.5 to 200 volumes per volume of catalystand per hour and with an aromatic compound/olefin molar ratio of between1:1 and 50:1.

In the implementation of the invention that comprises a second separatetransalkylation stage, the second stage can be carried out at atemperature of between about 100 and 500° C., preferably between 150 and400° C., under a pressure of between about 1.5 and 10 MPa (preferably 2to 7 MPa), with a liquid hydrocarbon flow rate (volumetric flow rate) ofabout 0.5 to 5 volumes per volume of catalyst and per hour, and with anaromatic compound/polyalkylaromatic compound molar ratio of about 2:1 to50:1.

EXAMPLES

The following examples illustrate this invention without, however,limiting its scope.

Example 1 Preparation and Shaping of a Silico-Aluminum Substrate SU1that is not in Accordance with the Invention

A precursor of matrix SU1 is prepared in the following way: in a firststep, a 30% sulfuric acid solution is added to a sodium silicatesolution. The amount of H₂SO₄ is defined so as to work at a setneutralization rate. The addition is done in two minutes while beingstirred at 600 rpm. The synthesis temperature is 60° C. The developmentperiod was set at 30 minutes. The stirring is maintained at 600 rpm, andthe temperature is that of the preceding stage. Then, Al₂(SO₄)₃ (500 ml)is added, and the concentration is set by the desired alumina content.The pH is not regulated and is set by the desired alumina content. Theaddition is done in 10 minutes. The stirring is still set at 600 rpm,and the temperature is the same as that of the preceding stages. Then,ammonia is added. The gel that is obtained is filtered by displacement.The washing is done with water at 60° C., 3 kg of water per kg of solidthat is contained in the gel. Then, an exchange with ammonium nitrateNH₄NO₃ (138.5 g/l) at 60° C. and 1.5 l per kg of solid that is containedin the gel is carried out. Finally, a supplemental washing with water at60° C. is done by displacement, 3 kg of water per kg of solid that iscontained in the gel. The gel that is obtained from this stage is mixedwith Pural boehmite powder such that the final composition of theanhydrous product is, at this stage of the synthesis, equal to 50%Al₂O₃-50% SiO₂.

The mixing is done in a Z-arm mixing machine. The extrusion is carriedout by passing the paste through a die that is equipped with orificeswith a 1.4 mm diameter. The thus obtained extrudates are dried at 150°C., calcined at 550° C., then calcined at 700° C. in the presence ofwater vapor.

The characteristics of the substrate are as follows:

-   -   The composition of substrate SU1 is 50.12% Al₂O₃-49.88% SiO₂.    -   The BET surface area of the substrate is 254 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.43        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 65        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.91.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.03 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.047 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.013 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.011 ml/g.    -   The pore volume, measured by mercury porosimetry and encompassed        in the pores with diameters of more than 500 Å, is 0.001 ml/g.    -   The X diffraction diagram contains the main lines that are        characteristic of the gamma-alumina, and in particular it        contains the peaks at one d encompassed between 1.39 and 1.40 Å        and the peaks at one d encompassed between 1.97 Å and 2.00 Å.    -   The atomic sodium content is 310+/−20 ppm. The atomic sulfur        content is 1500 ppm.

The substrate contains two silico-aluminum zones, whereby said zoneshave Si/Al ratios that are less than or greater than the overall Si/Alratio that is determined by X fluorescence. One of the zones has anSi/Al ratio that is determined by TEM to be 0.7, and the other zone hasan Si/Al ratio that is determined by TEM to be 0.98.

Example 2 Preparation and Shaping of a Silico-Aluminum Substrate SU2that is not in Accordance with the Invention

An alumina hydrate is prepared according to the teachings of U.S. Pat.No. 3,124,418. After filtration, the freshly prepared SU2 precipitate ismixed with a silicic acid solution that is prepared by decationizingresin exchange. The proportions of the two solutions are adjusted so asto reach a composition of 70% Al₂O₃-30% SiO₂ on the final substrate.This mixture is quickly homogenized in a commercial colloidal mill inthe presence of nitric acid such that the nitric acid content of thesuspension at the mill outlet is 8% relative to the silica-alumina mixedsolid. Then, the suspension is conventionally dried in a sprayer in aconventional way from 300° C. to 60° C. The thus prepared powder isshaped in a Z-arm in the presence of 8% nitric acid relative to theanhydrous product. The extrusion is carried out by passing the pastethrough a die that is equipped with orifices with a 1.4 mm diameter. Thethus obtained extrudates are dried at 150° C., then calcined at 550° C.,then calcined at 750° C. in the presence of water vapor.

The Characteristics of Substrate SU2 are as Follows:

-   -   The silica-alumina composition is 69.5% Al₂O₃ and 30.5% SiO₂.    -   The BET surface area is 250 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.45        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 70        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.021 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å, is 0.035 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.01 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.007 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains the main lines that are        characteristic of the gamma-alumina, and in particular it        contains the peaks at one d encompassed between 1.39 to 1.40 Å        and the peaks at one d encompassed between 1.97 Å to 2.00 Å.    -   The atomic sodium content is 250+/−20 ppm. The atomic sulfur        content is 2000 ppm.

The substrate contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.37.

Example 3 Preparation and Shaping of a Silico-Aluminum Substrate SU3that is not in Accordance with the Invention

The aluminum hydroxide powder was prepared according to the processdescribed in Patent WO 00/01617. The mean particle size of the aluminumhydroxide particles measured by laser granulometry is 40 microns. Thispowder is mixed with a silica sol that is prepared by decationizingresin exchange, then filtered on resin with a pore size of 2. Theconcentrations of silica sol and aluminum hydroxide powder are adjustedso as to obtain a final composition of 60% Al₂O₃ and 40% SiO₂. Theshaping is carried out in the presence of 15% nitric acid relative tothe anhydrous product. The mixing is done in a Z-arm mixing machine. Theextrusion is carried out by passing the paste through a die that isequipped with orifices with a 1.4 mm diameter. The thus obtainedextrudates are dried at 150° C., then calcined at 550° C., then calcinedat 750° C. in the presence of water vapor.

The characteristics of Substrate SU3 are as Follows:

-   -   The composition of the silica-alumina substrate is 59.7% Al₂O₃        and 40.3% SiO₂.    -   The BET surface area is 248 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.46        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 69        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.022 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.031 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.0105 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.0065 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains the main lines that are        characteristic of the gamma-alumina, and in particular it        contains the peaks at one d encompassed between 1.39 and 1.40 Å        and the peaks at one d encompassed between 1.97 Å and 2.00 Å.    -   The atomic sodium content is 200+/−20 ppm. The atomic sulfur        content is 800 ppm.

The substrate contains two silico-aluminum zones, whereby said zoneshave Si/Al ratios that are less than or greater than the overall Si/Alratio that is determined by X fluorescence. One of the zones has anSi/Al ratio that is determined by TEM to be 0.22, and the other zone hasan Si/Al ratio that is determined by TEM to be 0.85.

Example 4 Preparation and Shaping of a Silico-Aluminum Substrate SU4that is not in Accordance with the Invention

Substrate SU4 is obtained in the following manner:

The silica-alumina gels are prepared by mixing the sodium silicate andwater by sending this mixture over an ion exchange resin. A solution ofaluminum chloride hexahydrate in water is added to the decationizedsilica sol. So as to obtain a gel, ammonia is added, then theprecipitate is filtered, and washing with a concentrated water andammonia solution is carried out until the conductivity of the washingwater is constant. The gel that is obtained from this stage is mixedwith Pural boehmite powder so that the final composition of the mixedsubstrate of anhydrous product is, in this stage of the synthesis, equalto 60% Al₂O₃-40% SiO₂. This suspension is passed into a colloidal millin the presence of nitric acid. The added nitric acid content isadjusted so that the percentage at the outlet of the nitric acid mill is8% relative to the mixed solid oxide mass. This mixture is then filteredso as to reduce the amount of water in the mixed cake. Then, the cake ismixed in the presence of 10% nitric acid and then extruded. The mixingis done in a Z-arm mixing machine. The extrusion is carried out bypassing the paste through a die that is equipped with orifices with a1.4 mm diameter. The extrudates that are thus obtained are dried at 150°C., then calcined at 550° C., then calcined at 700° C. in the presenceof water vapor.

The characteristics of Substrate SU4 are as Follows:

-   -   The composition of the silica-alumina substrate is 60.7% Al₂O₃        and 39.3% SiO₂.    -   The BET surface area is 258 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.47        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 69        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å, to the        total mercury volume is 0.89.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.032 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.041 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.0082 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.0063 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains the main lines that are        characteristic of the gamma-alumina, and in particular it        contains the peaks at one d encompassed between 1.39 and 1.40 Å        and the peaks at one d encompassed between 1.97 Å and 2.00 Å.    -   The atomic sodium content is 200+/−20 ppm. The atomic sulfur        content is 800 ppm.

The substrate contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.63.

Example 5 Preparation of the Substrates of Catalysts According to theInvention (SU5 to SU8)

A zeolite Z1 with an Si/Al ratio measured by FX of 14.7, an Si/Alframework ratio measured by NMR of 19, sodium content of 260 ppm, meshparameter a=24.29 {hacek over (A)}, crystallinity rate of 88%, and BETsurface area equal to 838 m²/g is used.

5 g of zeolite Z1 that is described above and 95 g of precursors ofmatrices SU1 to SU4 converted to solid as described above are thenmixed. This mixing is done before the introduction into the extruder.The zeolite powder is wetted in advance and added to the matrixsuspension in the presence of nitric acid at 66% (7% by weight of acidper gram of dry gel) then mixed for 15 minutes. At the end of thismixing, the paste that is obtained is passed through a die that hascylindrical orifices with a diameter that is equal to 1.4 mm. Theextrudates are then dried for one night at 120° C. in air then calcinedat 550° C. in air, then calcined at 700° C. in the presence of watervapor.

Substrates SU5 to SU8 that contain 5% of zeolite Z1 converted intoanhydrous mass are thus obtained.

The characteristics of the substrates according to the invention are:

For Substrate SU5,

-   -   The composition of the matrix of the substrate is 50.1%        Al₂O₃-49.9% SiO₂.    -   The BET surface area of the substrate is 280 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.418        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 64        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.91.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.03 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.047 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.014 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z1 that was            introduced.    -   The atomic sodium content is 290+/−20 ppm. The atomic sulfur        content is 1500 ppm.

The matrix of the substrate contains two silico-aluminum zones, wherebysaid zones have Si/Al ratios that are less than or more than the overallSi/Al ratio that is determined by X fluorescence. One of the zones hasan Si/Al ratio that is determined by TEM to be 0.7, and the other zonehas an Si/Al ratio that is determined by TEM to be 0.98.

For Substrate SU6,

-   -   The silica-alumina composition of the matrix of the substrate is        69.5% Al₂O₃ and 30.5% SiO₂.    -   The BET surface area is 279 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.437        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 69        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.020 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.034 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.01 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.068 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z2.    -   The atomic sodium content is 240+/−20 ppm.    -   The atomic sulfur content is 1900 ppm.

The matrix of the substrate contains a single silico-aluminum zone withan Si/Al ratio that is determined by TEM microprobe to be 0.37.

The Characteristics of Substrate SU7 are as Follows:

-   -   The composition of the silica-alumina matrix is 59.7% Al₂O₃ and        40.3% SiO₂.    -   The BET surface area is 283 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.45        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.021 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.030 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.063 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z1.    -   The atomic sodium content is 190+/−20 ppm. The atomic sulfur        content is 800 ppm.

The matrix contains two silico-aluminum zones, whereby said zones haveSi/Al ratios that are less than or more than the overall Si/Al ratiothat is determined by X fluorescence. One of the zones has an Si/Alratio that is determined by TEM to be 0.22, and the other zone has anSi/Al ratio that is determined by TEM to be 0.85.

The characteristics of Substrate SU8 are as Follows:

-   -   The composition of the matrix of the silica-alumina substrate is        60.7% Al₂O₃ and 39.3% SiO₂.    -   The BET surface area is 287 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.46        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.89.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.031 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.040 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.008 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z1.    -   The atomic sodium content is 200+/−20 ppm. The atomic sulfur        content is 800 ppm.

The catalyst contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.63.

Example 6 Preparation of the Substrates of Catalysts SU9 to SU12According to the Invention

A zeolite Z2 with an Si/Al ratio measured by FX of 73, sodium content of102 ppm, mesh parameter a=24.15 {hacek over (A)}, crystallinity rate of44%, and BET surface area equal to 783 m²/g is used.

5 g of zeolite Z2 that is described above and 10 g of precursors ofsubstrates SU1 to SU4 that are described above are then mixed. Thismixing is done before the introduction into the extruder. The zeolitepowder is wetted in advance and added to the matrix suspension in thepresence of nitric acid at 66% (7% by weight of acid per gram of drygel) then mixed for 15 minutes. At the end of this mixing, the pastethat is obtained is passed through a die that has cylindrical orificeswith a diameter that is equal to 1.4 mm. The extrudates are then driedfor one night at 120° C. in air then calcined at 550° C. in air, thencalcined at 700° C. in the presence of water vapor.

Substrates SU9 to SU12 with 33% of zeolite Z2 are thus obtained.

The characteristics of the substrates according to the invention are:

For Substrate SU9,

-   -   The composition of the matrix of the substrate is 50.1%        Al₂O₃-49.9% SiO₂.    -   The BET surface area of the substrate is 283 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.418        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 64        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.91.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.03 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.047 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.014 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z2 that was            introduced.    -   The atomic sodium content is 290+/−20 ppm. The atomic sulfur        content is 1500 ppm.

The matrix of the substrate contains two silico-aluminum zones, wherebysaid zones have Si/Al ratios that are less than or more than the overallSi/Al ratio that is determined by X fluorescence. One of the zones hasan Si/Al ratio that is determined by TEM to be 0.7, and the other zonehas an Si/Al ratio that is determined by TEM to be 0.98.

For Substrate SU10, the Characteristics are as Follows:

-   -   The silica-alumina composition of the matrix of the substrate is        69.5% Al₂O₃ and 30.5% SiO₂.    -   The BET surface area is 279 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.438        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 69        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.020 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.034 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.013 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.0068 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The B/L ratio of the matrix is 0.12.    -   The packing density of the substrate is 0.79 g/cm³.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z2.    -   The atomic sodium content is 240+/−20 ppm. The atomic sulfur        content is 1900 ppm.

The matrix of the substrate contains a single silico-aluminum zone withan Si/Al ratio that is determined by TEM microprobe to be 0.37.

The Characteristics of Substrate SU11 are as Follows:

-   -   The composition of the silica-alumina matrix is 59.7% Al₂O₃ and        40.3% SiO₂.    -   The BET surface area is 275 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.45        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.021 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.030 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z2.    -   The atomic sodium content is 190+/−20 ppm. The atomic sulfur        content is 800 ppm.

The B/L ratio of the matrix is 0.12.

The packing density of the substrate is 0.795 g/cm³.

The NMR MAS 27A1 spectra of the matrix of the catalysts show twoclusters of separate peaks. A first type of aluminum whose maximumresonates toward 10 ppm extends between −100 and 20 ppm. The position ofthe maximum suggests that these radicals are essentially of AlVI type(octahedral). A second type of minority aluminum whose maximum resonatestoward 60 ppm extends between 20 and 100 ppm. This cluster can bedecomposed into at least two radicals. The predominant radical of thiscluster would correspond to Al_(IV) atoms (tetrahedral). The proportionof octahedral Al_(VI) is 70%.

The matrix contains two silico-aluminum zones, whereby said zones haveSi/Al ratios that are less than or more than the overall Si/Al ratiothat is determined by X fluorescence. One of the zones has an Si/Alratio that is determined by TEM to be 0.22, and the other zone has anSi/Al ratio that is determined by TEM to be 0.85.

The Characteristics of Substrate SU12 are as Follows:

-   -   The composition of the matrix of the silica-alumina substrate is        60.7% Al₂O₃ and 39.3% SiO₂.    -   The BET surface area is 284 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.46        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.89.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.031 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.040 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.008 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z2.    -   The atomic sodium content is 200+/−20 ppm. The atomic sulfur        content is 800 ppm.

The matrix contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.63.

Example 7 Preparation of the Substrates of Catalysts According to theInvention (SU13 to SU16)

A zeolite Z3 as described in U.S. Pat. No. 5,601,798 is used. Thiszeolite is prepared according to the method that is described in Example52, Table 16. The mesopore volume that is obtained is 0.36 cm³/g. Themesh parameter a is 24.34 {hacek over (A)}, and the crystallinity rateis 75%. 5 g of zeolite Z3 that is described above and 95 g of precursormatrices of substrates SU1 to SU4 converted to solid as described aboveare then mixed. This mixing is done before the introduction into theextruder. The zeolite powder is wetted in advance and added to thematrix suspension in the presence of nitric acid at 66% (7% by weight ofacid per gram of dry gel) then mixed for 15 minutes. At the end of thismixing, the paste that is obtained is passed through a die that hascylindrical orifices with a diameter that is equal to 1.4 mm. Theextrudates are then dried for one night at 120° C. in air then calcinedat 550° C. in air, then calcined at 700° C. in the presence of watervapor.

Substrates SU13 to SU16 with 5% of zeolite Z3 are thus obtained.

The characteristics of the substrates according to the invention are:

For Substrate SU13,

-   -   The composition of the matrix of the substrate is 50.1%        Al₂O₃-49.9% SiO₂.    -   The BET surface area of the substrate is 280 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.425        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 64        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.91.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.03 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.047 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.013 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.011 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z3.    -   The atomic sodium content is 290+/−20 ppm. The atomic sulfur        content is 1500 ppm.

The matrix of the substrate contains two silico-aluminum zones, wherebysaid zones have Si/Al ratios that are less than or more than the overallSi/Al ratio that is determined by X fluorescence. One of the zones hasan Si/Al ratio that is determined by TEM to be 0.7, and the other zonehas an Si/Al ratio that is determined by TEM to be 0.98.

For Substrate SU14, the Characteristics of the Substrates are asFollows:

-   -   The silica-alumina composition of the matrix of the substrate is        69.5% Al₂O₃ and 30.5% SiO₂.    -   The BET surface area is 276 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.438        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 69        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.020 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.034 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z3.    -   The atomic sodium content is 240+/−20 ppm. The atomic sulfur        content is 1900 ppm.

The matrix of the substrate contains a single silico-aluminum zone withan Si/Al ratio that is determined by TEM microprobe to be 0.37.

The Characteristics of Substrate SU15 are as Follows:

-   -   The composition of the silica-alumina matrix is 59.7% Al₂O₃ and        40.3% SiO₂.    -   The BET surface area is 275 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.455        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.021 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.030 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z3.    -   The atomic sodium content is 190+/−20 ppm. The atomic sulfur        content is 800 ppm.

The matrix contains two silico-aluminum zones, whereby said zones haveSi/Al ratios that are less than or more than the overall Si/Al ratiothat is determined by X fluorescence. One of the zones has an Si/Alratio that is determined by TEM to be 0.22, and the other zone has anSi/Al ratio that is determined by TEM to be 0.85.

The Characteristics of Substrate SU16 are as Follows:

-   -   The composition of the matrix of the silica-alumina substrate is        60.7% Al₂O₃ and 39.3% SiO₂.    -   The BET surface area is 284 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.46        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 68        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.89.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.031 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.040 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.008 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z3.    -   The atomic sodium content is 200+/−20 ppm. The atomic sulfur        content is 800 ppm.

The catalyst contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.63.

Example 8 Preparation of the Substrates of Catalysts (SU17 to SU20)

A zeolite Z4 that has an Si/Al(FX) ratio of 50, a sodium content of 154ppm, a crystallinity of 60%, and an SBET of 777 m²/g is used.

60 g of zeolite Z4 that is described above and 40 g of precursors ofsubstrates SU1 to SU4 converted to solid that are described above arethen mixed. This mixing is done before the introduction into theextruder. The zeolite powder is wetted in advance and added to thematrix suspension in the presence of nitric acid at 66% (7% by weight ofacid per gram of dry gel) then mixed for 15 minutes. At the end of thismixing, the paste that is obtained is passed through a die that hascylindrical orifices with a diameter that is equal to 1.4 mm. Theextrudates are then dried for one night at 120° C. in air then calcinedat 550° C. in air, then calcined at 700° C. in the presence of watervapor.

Substrates SU17 to SU20 with 60% of zeolite Z4 are thus obtained.

The characteristics of the substrates according to the invention are:

For Substrate SU17,

-   -   The composition of the matrix of the substrate is 50.1%        Al₂O₃-49.9% SiO₂.    -   The BET surface area of the substrate is 380 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.485        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 34        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.91.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.03 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.047 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.015 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.012 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z4.    -   The atomic sodium content is 290+/−20 ppm. The atomic sulfur        content is 1500 ppm.

The matrix of the substrate contains two silico-aluminum zones, wherebysaid zones have Si/Al ratios that are less than or more than the overallSi/Al ratio that is determined by X fluorescence. One of the zones hasan Si/Al ratio that is determined by TEM to be 0.7, and the other zonehas an Si/Al ratio that is determined by TEM to be 0.98.

For Substrate SU18, the Characteristics of the Substrates are asFollows:

-   -   The silica-alumina composition of the matrix of the substrate is        69.5% Al₂O₃ and 30.5% SiO₂.    -   The BET surface area is 376 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.48        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 39        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.020 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.034 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.011 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The lines that are characteristic of zeolite Z4.    -   The atomic sodium content is 230+/−20 ppm. The atomic sulfur        content is 1900 ppm.

The matrix of the substrate contains a single silico-aluminum zone withan Si/Al ratio that is determined by TEM microprobe to be 0.37.

The Characteristics of Substrate SU19 are as Follows:

-   -   The composition of the silica-alumina matrix is 59.7% Al₂O₃ and        40.3% SiO₂.    -   The BET surface area is 375 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.485        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 38        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.9.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.021 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.030 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.011 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.010 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z4.    -   The atomic sodium content is 190+/−20 ppm. The atomic sulfur        content is 800 ppm.

The matrix contains two silico-aluminum zones, whereby said zones haveSi/Al ratios that are less than or more than the overall Si/Al ratiothat is determined by X fluorescence. One of the zones has an Si/Alratio that is determined by TEM to be 0.22, and the other zone has anSi/Al ratio that is determined by TEM to be 0.85.

The Characteristics of Substrate SU20 are as Follows:

-   -   The composition of the matrix of the silica-alumina substrate is        60.7% Al₂O₃ and 39.3% SiO₂.    -   The BET surface area is 384 m²/g.    -   The total pore volume, measured by nitrogen adsorption, is 0.485        ml/g.    -   The mean pore diameter, measured by mercury porosimetry, is 38        Å.    -   The ratio between volume V2, measured by mercury porosimetry,        encompassed between D_(mean)−30 Å and D_(mean)+30 Å to the total        mercury volume is 0.89.    -   Volume V3, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+30 Å is 0.031 ml/g.    -   Volume V6, measured by mercury porosimetry, encompassed in the        pores with diameters of more than D_(mean)+15 Å is 0.040 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 140 Å is 0.011 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 160 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 200 Å is 0.006 ml/g.    -   The pore volume, measured by mercury porosimetry, encompassed in        the pores with diameters of more than 500 Å is 0.001 ml/g.    -   The X diffraction diagram contains:        -   The main lines that are characteristic of the gamma-alumina,            and in particular it contains the peaks at one d encompassed            between 1.39 to 1.40 Å and the peaks at one d encompassed            between 1.97 Å to 2.00 Å, and        -   The main lines that are characteristic of zeolite Z4.    -   The atomic sodium content is 190+/−20 ppm. The atomic sulfur        content is 800 ppm.

The matrix contains a single silico-aluminum zone with an Si/Al ratiothat is determined by TEM microprobe to be 0.63.

Example 9 Preparation of Catalysts for the Process of the Invention (C5to C20) and Catalysts that are not in Accordance with the Invention (C1to C4)

Catalysts C1 to C20 are obtained starting from substrates SUx in theform of extrudates. They are obtained by dry impregnation of an aqueoussolution that contains platinum salts (chloroplatinic acid or tetramineplatinum chloride) and/or fluorine salts (ammonium bifluoride NH₄HF₂)of, respectively, substrates SUx, in the form of extrudates and whosepreparations have been described respectively in Examples 1, 2, 3, 4, 5,6, 7 and 8. After maturation at ambient temperature in a water-saturatedatmosphere, the impregnated extrudates are dried at 120° C. for onenight, then calcined at 400° C. under dry air. TABLE 1 Contents ByWeight of F, Cl, Pt of Catalysts C1 to C20 C1 C2 C3 C4 C5 C6 C7 C8Substrate SU1 SU2 SU3 SU4 SU5 SU6 SU7 SU8 % Al₂O₃/ 50/50 70/30 60/4060/40 50/50 70/30 60/40 60/40 % SiO₂ % Zeolite 0 0 0 0 5 5 5 5 F (% by 00 0 0 0 1.5 3.1 4.8 Weight)/ Catalyst Cl (% by 0 0 0 0 0.81 0.82 0.790.80 Weight) Pt (% by 0 0 0.3 0.3 0 0.3 0.3 0.3 Weight) C9 C10 C11 C12C13 C14 C15 C16 Substrate SU9 SU10 SU11 SU12 SU13 SU14 SU15 SU16 %Al₂O₃/ 50/50 70/30 60/40 60/40 50/50 70/30 60/40 60/40 % SiO₂ % Zeolite33 33 33 33 5 5 5 5 F (% by 0 1.6 0 1.5 0 1.5 3.1 4.8 Weight)/ CatalystCl (% by 0 0 0 0 0.81 0.82 0.79 0.80 Weight) Pt (% by 0 0 0.3 0.3 0.30.3 0.3 0.3 Weight) C17 C18 C19 C20 Substrate SU17 SU18 SU19 SU20 %Al₂O₃/ 50/50 70/30 60/40 60/40 % SiO₂ % Zeolite 60 60 60 60 F (% by 01.6 0 1.5 Weight)/ Catalyst Cl (% by 0 0 0 0 Weight) Pt (% by 0 0 0.30.3 Weight)

Example 10 Evaluation of Catalysts C1 to C20 in Terms of Alkylation ofBenzene

A catalytic reactor that comprises a reaction zone that contains 50 cm³of prepared catalyst according to Example 9 is used.

The operating conditions for the alkylation of the benzene by dodecene-1are as follows:

-   -   Temperature: 135° C.    -   Pressure: 4 MPa    -   VVH=1 h⁻¹ (cm³ of benzene+dodecene-1 per cm³ of catalyst and per        hour)    -   Benzene/dodecene⁻¹ molar ratio 1:30

A feedstock that contains 72% by weight of benzene and 28% by weight ofdodecene-1 is prepared. This feedstock is introduced at the inlet of thecatalytic reactor where the alkylation reaction takes place.

The catalytic performance levels are recorded in Table 2 by expressingthe number of hours of operation with a conversion of >95% and thelinearity of the alkyl-benzenes that are formed. TABLE 2 CatalyticPerformance Levels of Catalysts C1 to C20 in Terms of Alkylation ofBenzene C1 C2 C3 C4 C5 C6 C7 C8 Number of 35 36 35.5 36.2 45 45 47 47Hours/ Conversion >95% Linearity of the 91.8 91.9 91.9 92.1 91.9 92.192.5 93.1 Alkyl-benzenes (%) C9 C10 C11 C12 C13 C14 C15 C16 Number of 4548 47 50 46 49 47 51 Hours/ Conversion >95% Linearity of the 92.5 92.992.3 93.2 93.2 93.5 92.9 93.6 Alkyl-benzenes (%) C17 C18 C19 C20 Numberof 46 47 46 48 Hours/ Conversion >95% Linearity of 91.5 91.7 91.5 91.8Alkyl-benzenes (%)

It appears that the catalysts according to the invention make itpossible to increase the operating time with a conversion of more than95% while maintaining a high percentage of linearity of thealkyl-benzenes that are formed.

The entire disclosures of all applications, patents and publications,cited herein and of corresponding French application No. 04/03.614,filed Apr. 5, 2004 are incorporated by reference herein.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention and, withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

1. A catalytic process for the production of at least one compoundselected from the group consisting of 2-, 3-, 4-, 5-, and6-phenylalkanes, said process comprising alkylation of an aromaticcompound with a feedstock containing at least one olefin having at least9 carbon atoms per molecule, wherein the process is conducted in thepresence of a catalyst that comprises at least one substrate comprisingan intimate mixture of (A) at least one zeolite or a mixture of zeolitesand (B) a non-zeolitic silica-alumina matrix, said matrix containing anamount of more than 5% by weight and less than or equal to 95% by weightof silica (SiO₂), said catalyst exhibiting the followingcharacteristics: a mean pore diameter, measured by mercury porosimetry,encompassed between 20 and 140 Å, a total pore volume, measured bymercury porosimetry, encompassed between 0.1 ml/g and 0.6 ml/g, a totalpore volume, measured by nitrogen porosimetry, encompassed between 0.1ml/g and 0.6 ml/g, a BET specific surface area encompassed between 100and 850 m²/g, a packing density after calcination of more than 0.65g/cm³, a pore volume, measured by mercury porosimetry, encompassed inthe pores with diameters of more than 140 Å, of less than 0.1 ml/g, apore volume, measured by mercury porosimetry, encompassed in the poreswith diameters of more than 160 Å, of less than 0.1 ml/g, a pore volume,measured by mercury porosimetry, encompassed in the pores with diametersof more than 200 Å, of less than 0.1 ml/g, a pore volume, measured bymercury porosimetry, encompassed in the pores with diameters of morethan 500 Å, of less than 0.1 ml/g, an X-ray diffraction diagram thatcontains at least the main lines that are characteristic of at least oneof the transition aluminas contained in the group of alpha-, rho-, chi-,eta-, gamma-, kappa-, theta- and delta-aluminas, a pore distributionsuch that the ratio between volume V2, measured by mercury porosimetry,encompassed between D_(mean)−30 Å and D_(mean)+30 Å, to the totalmercury volume is more than 0.6, such that volume V3, measured bymercury porosimetry, encompassed in the pores with diameters of morethan D_(mean)+30 Å, is less than 0.1 ml/g, and such that volume V6,measured by mercury porosimetry, encompassed in the pores with diametersof more than D_(mean)+15 Å, is less than 0.2 ml/g, and wherein saidprocess is conducted at a temperature of between 30 and 400° C., apressure of between 0.1 and 10 MPa, an hourly volumetric flow rate of0.05 to 200 h⁻¹, and an aromatic compound/olefin molar ratio of between1:1 and 50:1.
 2. A process according to claim 1, wherein the aromaticcompound is benzene.
 3. A process according to claim 1, wherein the porevolume, measured by mercury porosimetry, encompassed in the pores withdiameters of more than 500 Å is less than 0.05 ml/g.
 4. A processaccording to claim 1, wherein at least one zeolite is selected from theFAU-structural-type zeolites.
 5. A process according to claim 4, whereinat least one zeolite is selected from the group consisting of Y zeoliteand Y zeolites that have undergone a secondary treatment.
 6. A processaccording to claim 1, wherein at least one zeolite is selected from thegroup consisting of mordenite, beta, NU-87 and EU-1.
 7. A processaccording to claim 1, wherein the catalyst contains at least onehydro-dehydrogenating element that is selected from the group consistingof the noble elements of group vm and the elements of group VIB of theperiodic table.
 8. A process according to claim 7, wherein the catalystcomprises at least one noble element of group VIII that is selected fromthe group consisting of platinum, palladium and ruthenium.
 9. A processaccording to claim 8, wherein the catalyst comprises platinum andpalladium.
 10. A process according to claim 7, wherein the content bymass of metals of group VIII or group VIB in metallic form or in oxideform is encompassed between 0.005 and 5% by weight.
 11. A processaccording to claim 1, wherein the catalyst comprises at least onehalogen.
 12. A process according to claim 11, wherein the halogen ischlorine or fluorine.
 13. A process according to claim 12, wherein thehalogen is fluorine.
 14. A process according to claim 11, wherein thecontent by mass of the halogen is encompassed between 0.5 and 10% byweight.
 15. A process according to claim 1, wherein the catalystexhibits a bed crushing value of more than 0.5 MPa.
 16. A processaccording to claim 1, wherein the catalyst substrate exhibits an aciditythat is measured by infrared tracking of the thermodesorption of thepyridine such that the B/L ratio (number of Bronsted sites/number ofLewis sites) of the silica-alumina matrix is encompassed between 0.05and
 1. 17. A process according to claim 1, wherein the non-zeoliticsilica-alumina matrix comprises a single silico-aluminum zone that hasan Si/Al ratio that is equal to the overall Si/Al ratio that isdetermined by X-ray fluorescence and is less than 2.3.
 18. A processaccording to claim 1, wherein the non-zeolitic silica-alumina matrixcomprises at least two silico-aluminum zones that have Si/Al ratios thatare less than or more than the overall Si/Al ratio determined by X-rayfluorescence.
 19. A process according to claim 1, wherein the reactionsof alkylation and transalkylation take place in a combined reactionzone.
 20. A process according to claim 19 comprising the followingsuccessive stages in the combined alkylation and transalkylation zone:Reaction of the aromatic compound with a feedstock that contains atleast one olefin (olefinic feedstock) upon contact with the catalystthat is based on silica-alumina (alkylation reaction), Fractionation ofthe resultant product so as to collect separately a first fractioncontaining unconverted aromatic compound, a second fraction containingat least one olefin that is initially present in the feedstock(unconverted), a third fraction that contains 2-, 3-, 4-, 5- and6-phenylalkanes, and a fourth fraction that contains at least onepoly-alkylaromatic compound (or poly-alkylaromatic fraction), wherebythe latter is then at least partially recycled to said reaction zonewhere it reacts with the aromatic compound upon contact with thecatalyst, so as to be at least partially transalkylated (transalkylationreaction), and Collection of a mixture of 2-, 3-, 4-, 5- and6-phenylalkanes.
 21. A process according to claim 20, wherein the firstfraction that contains the unconverted aromatic compound is at leastpartially recycled to the joint reaction zone.
 22. A process accordingto claim 20, wherein the second fraction that contains at least oneunconverted olefin is at least partially recycled in the reaction zone.23. A process according to claim 20, wherein heavy alkylaromaticcompounds are removed from the recycled portion of the fourth fractionby fractionation.
 24. A process according to claim 1, wherein thealkylation reaction is carried out in the presence of hydrogen.
 25. Aprocess according to claim 1, wherein the feedstock that contains atleast one olefin for comprises the most part of paraffins.